A digital camera has an imaging sensor which forms its heart. The imaging sensor is where light rays travelling through the lens barrel gets focused on to in order to form a sharp image. This sensor is what separates a digital camera from an analog one.
An analog camera uses either a film or a photo plate to focus light on. There are no electronic circuitry that transfers captured light onto the image processor. There is no image processor, unlike digital cameras. Such cameras captures light by sensitizing the film medium at the back of the camera. That film is then process in a lab to produce negatives which are then used to produce prints / scanned by a negative scanner. Also there are no built-in Color Filter Array (CFA). The mechanical controls of the camera is what controls the shutter and helps in advancing the film after each shot.
The digital sensor is actually composed of millions of tiny light sensitive photo-diodes. These photo diodes are similar to small pins. On the top of a typical photo diode is a tiny micro-lens that filters out all but one color in the visible spectrum. These micro-lenses are arranged in a particular arrangement or array.
This is true for all light sensors and it is also referred to as a Color Filter Array (CFA). The most popular CFA is the Bayer array. In other words the pixels are capped with tiny micro lenses which filter all wave length of light except for one particular wave length. A standard pixel can come with either a Red, Green or Blue color filter. On any standard sensor there are twice as many Green filters as Red or Blue filters.
We just finished reading about pixels. We have a pretty good idea about what it is. But more than pixels you will hear about the term megapixels often. As a matter of fact megapixels drive not only the sales figures of DSLRs, but all digital cameras!
It is often placed as an argument that larger the number of megapixels, better is the image quality. We will learn very soon that this argument is only partly correct. It seems that manufacturers and stores selling cameras are bent on pushing a camera on the sole USP of megapixel. As if nothing else matters. But what are megapixels and how would you justify that a larger number of these would produce a better image?
Megapixels, simply explained equal to one million pixels. In other words 1 megapixel = 1,000,000 pixels. When you hear that a particular camera has 20 megapixel it means that the camera has 20 million pixels. That’s a lot of pixels! Remember, we have just learnt that each pixel is a photo-diode.
Now, the question is does more megapixel mean better image quality? The answer is both yes and no. Your digital images are formed by the pixels. One tiny dot on a digital image is roughly equivalent to the size of a pixel. More the dots, more are the details. This can be easily demonstrated by taking two images of the exact same scene, shot by two similar cameras with the same lens under the same lighting conditions. Except, that one of the cameras has a 24.1 megapixel sensor and the other one has a 50.6 megapixel sensor.
You will notice that the image that was shot with a 50.6 megapixel camera has way too much detail in it than the one shot with a 24 megapixel sensor. Why? Because the larger number of megapixel allowed the sensor to capture even the tiniest aspects of the image with greater detail.
Another advantage of a higher number of megapixel is that you can print big. The printing industry uses a standard 300 DPI for printing images. A 50.6 megapixel sensor will be able to produce an image of the pixel dimension 8688 x 5792 pixels. On the other hand a 24.1 megapixel sensor will be able to produce an image of the dimension 6000 x 4000 pixels.
Now let’s say that you want to print your vacation images. With the 50.6 megapixel camera you would able to squeeze in a large 20” x 30 print. On the other hand with the 24.1 megapixel camera the largest you would be able to print is 11” x 14”. Needless to say with a larger resolution (larger megapixel count) you would be able to print large without pixilating the prints.
One major disadvantage of higher megapixel is the larger file size. Larger file size means your memory cards would have be of a higher capacity. Smaller capacity memory cards will exhaust much quicker. You will also need a much larger backup drive to store all your RAW and JPEG images.
Plus, a larger file size means additional pressure on the buffer. Buffer speed on your camera determines how suitable it is for shooting sports and other continuous shooting requirements. Larger file size takes more time to process and clear buffer thereafter. Therefore, it has a direct effect on the continuous shooting speed of your camera.
Thus, more megapixels means better images, right? No! More megapixels certainly means a greater amount of detail. But it in no way means that your images are going to be ‘better’. Though the term better is a bit dubious and it has much wider ramifications, we are not going to go into the details.
If you are mainly going to share your images online, there is no reason to go for a larger megapixel camera. If you are going to watch your images on your 4K TV you only need 4096 x 2160 = 8.84 megapixels. For sharing on social media you don’t even need that many megapixel.
A pro photographer who knows what s/he is doing can easily make stunning imagery with a 10 megapixel camera. On the other hand, someone who does not know how to use manual mode will probably end up getting snapshot styled imagery even if s/he is given a 50 megapixel top of the line DSLR.
Bayer Demosaicing / Interpolation
This is a complex processing mechanism that takes the incomplete color information in the form of red, blue and green and then convert that into a complete image with all the color information. Most common sensors use the Bayer Algorithm This algorithm has twice as many Green filters as Red or Blue filters. The process of converting that information into a proper image is known as Demosaicing and is done by the built-in image processor on the camera or can also be done off-camera using any third party image processing software. This process is also referred to as Interpolation.
Full-frame sensors basically mimic the size of the older 35mm film. Full-frame sensors are typically 36mm x 24mm in dimension and therefore the image is roughly the size of what a 35mm film would be. Though in itself the size of the sensor does not mean anything, there are critical advantages to using a larger sensor.
The term APS-C means Advanced Photo System – Classic. In a much easier to understand meaning it means a sensor that is smaller than a full-frame. APS-C sensors are smaller in size compared to full-frame sensors. How small exactly? Well there is no standardized sizes. Different manufacturers have their own sensor sizes. Roughly, they mimic the size of the older film negatives of the same name. These negatives had the size 25.1 x 16.7mm.
For example Nikon’s D7200, an APS-C sensor powered camera, has a sensor size of 23.5mm x 15.6mm. On the other hand Canon’s 7D Mark II, another APS-C sensor powered camera, has a sensor size of 22.4 x 15mm. The sensor size can vary even between two cameras of the same make and segment. For example, the Canon Rebel T6i, which also has an APS-C sensor, but measuring 22.3 x 14.9mm.
The image circle of a lens, as the name suggests, is a round one. However, the sensor at the back of the camera is a rectangular one. This is a classic case of taking a square peg to attempt to fill in a round hole. A lens designed for a particular sensor format will cover almost whole of the frame with the exception of the four corners. This four corners will show some amount of darkening depending on the sensor design and the lens being used. This phenomenon is known as vignetting.
Vignetting tends to be present on most lenses with a little bit of exception. However, vignetting tends to be extreme when shooting with a lens designed for a crop sensor format on a full-frame camera. This is because the image circle of the lens will not cover the whole of the sensor.
Vignetting can be easily corrected, at least when the lens and the sensor are compatible, by using the lens profile correction option in Photoshop and Lightroom.
Crop factor denotes how much a particular sensor is smaller or larger than a 35mm (full-frame) sensor. This is actually expressed as a ratio like 1.5x or 1.6x. Crop factor affects focal length of a lens. Not the actual focal length, but the effective one. Let us understand this is in more detail.
If you multiply the crop factor with the focal length of the lens you will find the new effective focal length. Let’s say that a sensor is marked as having a crop factor of 1.5x (e.g., Nikon APS-C cameras have a crop factor of 1.5x). Now, let’s say that you mount a 50mm lens on it. This lens is designed for the full-frame sensor. The smaller sensor will use only a portion of the image coming through the lens. That happens to be the center part of the image coming through the lens. In effect it would appear that you are using a longer lens. Therefore, the result is identical to what it would be if you were using a 75mm lens.
Any sensor that is smaller than a full-frame sensor is referred to as a crop sensor. A crop sensor crops out the edges of the scene from what would have been captured using a full-frame sensor camera. Resultantly, it would appear that the lens is zoomed in. In other words the lens’ effective focal length gets extended when using with a crop sensor camera.
Focal length has nothing to do with the size of the lens barrel. Focal length denotes the distance between the point where light rays converge and the digital sensor at the back of the camera where the image is finally formed. This distance is measured in mm. Roughly, it is a measurement of the optical center of the lens to the sensor at the back of the camera.
Longer that distance or focal length, the longer a lens can see. In effect that also means smaller the viewing angle of the lens. Shorter that distance, the wider is the viewing angle and the shorter the distance that the lens can see.
In other words a long lens something like a 70 – 200mm telephoto can see a much thinner slice of the scene compared to a wide angle lens something in the range of 14 – 24mm.
Dynamic Range is a term that denotes how many stops of intensities of light a digital sensor can see between the whitest white and the blackest black in a scene. The term is also applied for all types of cameras as well as for other imaging devices with different annotations.
A camera with a higher dynamic rage will produce images with higher contrast levels. A camera with a high dynamic range will also likely to have less problems with color banding or aliasing that we see when photographing certain scenes. This frequently happened with older digital cameras.
This happens because most outdoor scenes have a greater dynamic range than an average camera can record. This results in the camera trying to ‘even’ the scene out and in the process banding appeared in the images.
Modern digital cameras can record in 14 bit RAW which gives them a lot of latency. An incredible amount of data can thus be recorded in a lossless format. This data is then available when you are post-processing the images.
Incident light denotes the light that falls on a subject. The terms Incident Light is relevant because of metering. Incident light metering is the best way to meter a scene. This is because when you measure incident light it does not matter whether the subject or the scene has bright colors or dark ones. Incident light metering is also the faster of the two methods to measure light in a given scene.
Reflected Light denotes light that is reflected off of a surface. Just like Incident light it is relevant because of light metering. Reflected light metering is a poor way to meter a scene because it can skew the metering sensors depending on how bright or dark the scene is. Thus, if the scene is bright / has brighter colors, it is likely to tell a light meter that the scene is bright. On the other hand if the scene has an overbearing amount of dark colors it is likely to tell the light meter that the scene is too dark. Reflected Light metering technique is also the slower of the two methods to meter light.
A Light Meter is a device that measures the amount of light falling on / reflected off of a scene. It basically helps you to set the right exposure values for an ideal exposure of the scene / subject. There are two kinds of light meters – handheld and built-in.
Hand-held Light Meters
A hand-held light meter is an optical device that measures light falling on a scene. It uses, generally, a translucent dome type structure that has a light sensor built inside it. The dome structure is aimed at the general direction of the camera when you need to meter a scene.
The device can also be used to measure reflected light. Hand-held light meters are far more accurate when measuring the correct light value of a scene. This is because they are dependent on the actual incident light and not the light reflected off of a scene.
Built-in light Meters
These are a type of light meters that are built into a camera and depend on the light reflected off of a scene in order to measure the light value of the scene. These type of light meters easily get skewed because depending on the average colors in a scene the amount of brightness measured in the scene varies with it. So, for the same amount of light a scene with darker colors will be metered to be too dark (therefore suggesting you push the exposure) and a scene with brighter colors will be measured as too bright (therefore suggesting that you underexpose the shot).
Matrix metering is a built-in metering mode on all digital cameras. In this mode the whole scene is divided into zones. These zones are individually measured for the amount of brightness and shadows and accordingly the right exposure settings are used that would give an average exposure for the whole of the scene. As an average exposure is given this mode is ideally suitable for the purpose of shooting landscapes and for scenes that have a fairly even lighting situation across the scene. This mode takes into account almost the whole of the scene when metering. However, some amount of preference is given to the AF point that is active. This is why this mode is suitable when you have a subject that is off-center and you are focusing on it.
This mode takes into account the center of the frame. Everything else in the frame is disregarded for the purpose of metering. Thus, if you have a subject that is right about at the middle of the frame, this metering mode is perfect. This mode works for backlit situations as well where the key light is behind the subject and therefore you need to be able to meter only the face. This metering mode will also work in situations where you place your subject intentionally towards the middle of the frame. E.g., flower photography or macro photography.
Spot metering as the name suggests will take into account only a small area of the frame for the purpose of metering a scene. That area is usually 5-10%. In some cameras you can select an AF point and the camera’s metering mechanism will meter the area around that AF point. In other camera systems the spot is not selectable and lies at the center of the frame. The reason why the Spot metering mode is such a useful mode is because it has the inherent ability to meter a very small area. It is therefore possible to aim at something that is neutral (or middle-grey) and be able to make a very tight estimate of what would be an accurate exposure value for the whole f the scene. This is something that all hand-held light meters allow you to do. A reason why these light meters are considered so accurate.
Partial metering is a metering mode that is exclusive to Canon systems only. Nikon systems don’t have this mode. This mode is exactly like the Spot metering mode that we saw above with an exception. That being that the camera meters a slightly larger area of the frame for metering purposes– about 12 – 15%. Partial metering would be suitable for use when you need to photograph something that is a bit larger. But not as large as the area covered by center-weighted metering. So things like flowers shot from a close distance, a house in the middle of a landscape scene are ideal for use with this metering mode.
Exposure value is a concept in photography. It measures the amount of light that the camera collects as a result of a particular combination of shutter speed and aperture. Exposure value is actually a product of the shutter speed and aperture of your camera system. Exposure value is generally denoted as a number. Each number on the scale corresponds to a specific amount of light. Sliding down to the next higher or lower number means you go higher or lower about two stops of exposure. It is possible to arrive at the same EV using different combinations of shutter speed and aperture.
The term exposure compensation is used in conjugation with exposure value. Exposure compensation is all about using an exposure value either over or under of what a light meter suggests is correct for a scene. This is done specifically to push or pull the exposure based on what you think is the right exposure value for the scene. Exposure compensation is frequently used when using the built-in meter of your camera. This is because this is the meter that is likely to get the exposure value incorrect more often. To use exposure compensation press the symbol (+/-) and then turn the command wheel to depending on whether you need to over or under expose the scene.
Aperture is a small hole in the lens that allows light to pass through and enter the camera. Aperture can be enlarged or reduced depending on the requirements of the scene. In other words you can use a large aperture in order to collect a lot of light or a small aperture in order to reduce the amount of light. This obviously depends on what you envision and attempt at capturing.
Aperture is always expressed in f-stops and is written like this – f/2, f/2.8, f/4, f/5.6 and so on. Smaller the number on that scale, larger is the actual size of the aperture and vice versa. That means as you go down the table, aperture will continue to get smaller and smaller. Vice versa as you go up the table. Aperture also controls depth of field.
Shutter speed on the other hand denotes the length of time for which the shutter curtain remains open to collect light. The longer the shutter curtains remain open the more light the camera receives and vice versa. Shutter speed is always referred to as a fraction of a second. The faster is the shutter speed, the smaller is the fraction and vice versa. You will get fractions like 1/100, 1/200, 1/400, 1/800, 1/1600 and so on. As you go down the table shutter speed gets faster and faster, and slower and slower as you go up the table. Shutter speeds at 1 sec and faster are not expressed as fractions. They are expressed in the usual way – 1”, 2” and so on.
A term that is closely related with shutter speed and for god reason too is Image Stabilization. Image Stabilization is a mechanism that compensates for an inadvertent movement of the camera at the precise moment when an image is being made. The task of image stabilization is to ensure that the resulting image does not turn out to be blurry.
You use image stabilization every time you press down the shutter release of your camera without even realizing that you are doing so. Image Stabilization is engaged each time you half-press the shutter release button. That means both acquiring focus as well engaging the image stabilization works using the same button.
Image stabilization mechanism can be of two basic types. Either lens based or camera body based. Nikon and Canon are two major camera makers that produce cameras that have lens based image stabilization system. Pentax, Sony, Olympus and Samsung are camera makes that use body based image stabilization. Each of these manufacturers refer to their brand of image stabilization by different names. But they essentially do the same thing.
Body based image stabilization actually moves the sensor whereas lens based image stabilization moves tiny optics inside the lens. The result is the same. Every time the camera moves while making an image as a result of your hand moving, tiny elements inside the lens, or the sensor itself will move to compensate for that movement. Think of them as counterweights for balancing the weight of a tall building which is swaying in the wind.
There are advantages and disadvantages of both these types of stabilization mechanics. Body based image stabilization makes all compatible lenses stabilized by default. On the other hand manufacturers with lens based image stabilization produce two versions of their popular lenses. One with image stabilization and one without. Lenses with image stabilization costs more.
The argument in favor of body based image stabilization is that it is a better technique. This is because in order to get the full benefit of image stabilization you don’t have to buy special stabilized version of a lens. The argument against is that lens based image stabilization allows you to pay for exactly what you choose to use. Meaning, if you don’t need image stabilization you don’t have to pay extra for that. You can easily get a non-stabilized version of a lens and shoot to your heart’s fill.
A major advantage of lens based image stabilization is that when stabilization kicks in you can see the effect through the viewfinder. That way you don’t ‘hunt’ around for the subject when using lens based image stabilization systems. Composing is a lot easier that way.
On the other hand when you look through the viewfinder of a body based camera, the effects of image stabilization is not immediately seen. It will still do what it is supposed to do but composing through the viewfinder isn’t that easy.
Image Stabilization comes in different varieties. Let’s look at them.
There are different modes of image stabilization. The most important of them is the one that we use on an everyday basis – the plain vanilla mode. This mode simply ‘stabilizes’ any inadvertent movement of the camera while an image is being made.
To activate image stabilization you will need to gently half press the shutter release button. Immediately, the stabilization option will kick in and then continue to stabilize the image till you press down the shutter release completely to complete the exposure.
The second mode is slightly different. It engages exactly the same way as the first mode though. But in this mode only any perpendicular movements are countered for. Meaning when shooting if your hands move in an up and down motion image stabilization will kick in. If your hands move horizontally, however, image stabilization will not kick in.
This is mode is designed for the specific purpose of panning. Panning denotes moving your camera in a tracking motion following a subject that is moving. This mode is ideal for photographing sprinters, soccer players, wildlife moving in a straight line left to right of the frame (or right to left as the case may be) and so on. By not engaging image stabilization for horizontal movement of the camera, when you might be actually moving the camera for panning, this mode opens up a new dimension for photographing with a stabilized lens.
There is a yet another mode. A third mode which is designed for a different type of photography. In this mode image stabilization does not get engaged until you press the shutter release fully. By not engaging image stabilization till the very last second you get to see an actual depiction of the action in front you. This mode is ideal for subjects that are moving erratically. Such as a bunch of kids playing in the yard a humming bird, even a squirrel perched on a tree.
The letters ISO pronounced in unison isn’t an acronym, though it is sometimes used as one to describe the International Organization of Standardization. The closest similarity with the word ISO is ASA, another term that was used for the exact same purpose, to demonstrate the sensitivity of the imaging medium. Back in the days of analog photography that medium was film and these days it is the digital sensor.
Why ISO is important? ISO is closely linked with making images in low light. Low light is a situation when you would be forced to slow down the shutter or increase the aperture in order to capture a lot of light.
You might use a flash in such situations, but a flash isn’t always necessary. There are times when a flash can do more harm than good. A flash is a powerful beam of light which is very difficult to control. You don’t even have to use it on-camera to ruin a photo. Even an off-camera flash can be difficult to work with.
Plus, there are instances when tinkering with either aperture or shutter speed is not feasible. E.g., when you are shooting a portrait and you need to blur out the background and at the same time would want to shoot a sharp image with a fast shutter speed.
Basically, you need a way to be able to continue shooting with the same aperture and shutter speed, produce the same depth of field you originally went out to shoot and produce the same effect with the desired shutter speed. These are the times when you need to tinker the ISO.
ISO is expressed in numbers. So, you have numbers like 50, 100, 200, 400, 800, 1600 and so on. These are also expressed as stops. Note how the numbers on the scale doubles up at each stop. Please note ISO setting do not affect the amount of light that is collected by the sensor. It only affects what happens after that light is collected. That is why ISO is never considered as a part of Exposure Value.
ISO simplify amplifies the light signal. When the light signal is amplified, it accomplishes the same task as increasing the aperture size or dragging the shutter would have done.
Noise here refers to digital noise. You would be wondering what does noise got to do with digital photography right? Well noise is closely connected with ISO. As you increase ISO you will probably notice the effects of noise. You have probably seen noise in your own images without ever realizing why they occur.
Noise refer to the physical black and white dots that appear in a photo especially when you shoot at a higher ISO. If you shoot low light images quite a lot you should have come across. Look closely at the shadow areas of your images. Can you see the white and black specks? Those are noise. More specifically digital noise.
Digital noise can be best compared with static in sound transmission. Just like when you transmit sound between two points some amount of static is inevitable, digital noise too happens when light signals are captured by the sensor.
Digital noise is best seen when you shoot images in low light with a higher ISO number. These speckles or grains are seen easily around the shadow areas, because these are the areas where the sensor will try harder to ‘bring up’ the exposure.
The major effects of noise in image are the lack of detail and loss in dynamic range. Images shot at lower ISO will have a lot of detail. They also have good dynamic range (elaborated by greater contrast). When you choose a higher ISO number grains will reduce detail, introduce artefacts and you will lose a lot of detail in the process.
A common misconception about digital noise is that it appears only on images which are shot at a higher ISO. This is wrong. Digital noise is present in every image shot at every ISO. Even at ISO 100. However, at ISO 100 the amount of noise is very negligible compared to an image that was shot in low light and at ISO 3200.
The process of cancelling the noise present in an image is known as noise cancellation or noise suppression. There are many ways in which you can cancel noise. Some are done in-camera using built-in software. Others are done after the image has been downloaded on to a computer.
All contemporary cameras come with a built-in noise-cancellation application. The technique involves identifying noise and then applying a special algorithm that introduces a slight bit of blurring to reduce noise. This will invariably result in the image appearing plasticky.
The same noise suppression can be done in a dedicated image editing software. We would recommend using a dedicated image editing software, than using the built-in image processor of your camera (i.e., shoot in RAW instead of JPEG). Additionally, turn off the default noise suppression feature of you camera.
Shoot in RAW and import your images to your computer in order to do your own image processing including noise suppression manually. Photoshop and Lightroom are two very popular software for noise suppression. But there are others like TopazLabs DeNoise. The latter being a dedicated noise reduction suite
Depth of field
When you look at an image you can tell where the photographer had focused on. This is the area of the image that will be very sharp. The focus point was placed here. As you look beyond that sharpest area, you will notice that the image appears to be increasingly out of focus. The further you look away from the point of focus, the more it seems to be out of focus.
Having said that, even though a large part of the image is out of focus, some of it is still acceptably in focus. This acceptable amount of focus is known as depth of field. Smaller the aperture, larger is that acceptable area of focus. In other words larger depth of field. Larger the aperture, smaller is the acceptable area of focus. In other words smaller depth of field.
There are other parameters as well that also impact depth of field. That includes, the size of the sensor, the focal length of the lens, the subject to background distance and so on.
The technology of auto-focusing wasn’t around forever. Lenses were always focused manually using various different technologies. To describe auto-focusing one could say that it is the process where the camera / lens uses a built-in motor and sensor that aligns the focusing elements automatically in order to being the subject in sharp focus. The result will be a sharp image produced on the image plane.
Auto-focus is basically a time-saving technology. It saves critical moments trying to focus on something at a distance and instead produce an image in a shorter time frame by leaving the focusing task to the camera.
The technology of auto-focusing has evolved over the years from something which emitted sound waves (in Polaroid systems) in order to lock in focus, to the modern dual-pixel CMOS AF mechanism we find in latest Canon systems which looks for contrast to lock focus. The purpose of all of these technologies is the same – to bring a sharp focus of the subject on to the image plane.
The Japanese word bokeh is used in photography to denote the quality of the out of focus effect of your image and not just the out of focus effect alone. It is sometimes incorrectly referred to the blur that comes from using a wide open aperture. To explain it in an even simpler way, blur is not equal to bokeh. On the other hand bokeh does equal to blur.
Now, quality denotes the smoothness of the out of focus effect. There are certain aspects that determine the quality of the out of focus effect. The primary factor being the number of aperture diaphragm blades. The more the number of aperture diaphragm blades, the rounder and smoother the blur or out of focus effect will be.
Another factor that weigh in on bokeh is how wide the aperture can open up to. For lenses that have a small aperture (for example a kit lens with a maximum aperture of f/3.5) bokeh wouldn’t be that nice. On the other hand for an 85mm f/1.8 bokeh would be nice soft, rounded and very smooth.
There are many practical applications of bokeh. The most common application being to isolate a subject from its foreground and background. Portrait photography is one area where this is used quite often. Another area is macro and product photography. However, this is not an exhaustive list.
Selective focusing is the art of focusing on a specific area of the image. The purpose of this is to draw the attention of the viewer to a specific part / aspect of an image. Selective focusing uses several techniques. But the principle element of selective focusing is to use a wide aperture and utilize the shallow depth of field that creates.
A good example of selective focusing would be when you use a lens such as a 50mm f/1.4 or an 85mm f/1.8 or a 100mm f/2.8 macro to shoot something wide open. Only a small area of the frame, coinciding with the active AF point, is in sharp focus. Everything else is at varying degrees of sharpness.
This technique is often used in areas of wedding photography, portraitures and macro photography.
JPEG vs. RAW
Very simply, RAW is an untouched, un-manipulated format which has all the details of an image safely preserved and waiting to be adjusted manually by you. JPEG, on the other hand is a processed format. The original RAW image has been processed, either by the camera or an external application. The result is a file which has little to no scope of further alterations without significantly destroying the quality of that image.
RAW basically retains the original information as captured by the sensor. JPEG on the other hand compresses the information to improve the file size and to cull non-essential information. It is important to know that all cameras actually shoot in RAW by default. It is only after the image is shot is the camera processes it in JPEG. In some cameras you can prevent your camera from converting a RAW image to JPEG by switching to RAW mode.
Why would you shoot in RAW? Well to start off RAW is a lossless format. But is that all there is to it? As a matter of fact there is a lot more to it. RAW retains a larger amount of detail in both the shadow and the highlight regions. This is known as dynamic range. RAW images far outperform JPEG images in dynamic range.
How much to be precise? JPEG images can retain 256 levels of brightness between the brightest bright and the darkest dark regions in an image. It is also referred to as 8 bit. On the other hand RAW can retain from 4096 to 16384 levels of brightness. That is 12 to 14 bit depending on the camera make and model. The most immediate advantage of this higher level if information is that the images don’t have banding.
Since the original information is retained, you also have the opportunity to adjust things like white balance and exposure without destroying the image. This is the reason why professionals choose the RAW format because they can then choose the way they want to process their images as per their requirement.
Also, and this one is relevant for printing, you can control the color space of the image better by choosing the appropriate one depending on whether you are going to publish the images online or use them for print at output.
Continuous shooting Drive
Usually, when you press down the shutter button the shutter curtain opens to make the exposure and then resets for the next shot. This process happens only once. Continuous shooting drive denotes the ability to fire a number of frames one after the other. Nikon systems have three shooting modes, S (Single shot), CL (Continuous Low) and CH (Continuous High).
This depends on a number of factors. One of them is how fast the image processor is. The speed of the image processor denotes how quickly it can finish processing one frame and transfer it to the storage for the next frame. Modern high speed image processors can handle anything between 7 to 14 frames per second.
Another determining factor is whether you are shooting with continuous Auto Exposure and Auto Focusing or have locked both focus and exposure before the first frame is fired. In the first scenario the camera will acquire focus and adjust exposure before each frame. This slows down the overall speed. In the second scenario focus and exposure is locked before the first frame is fired. That means the camera gains some extra seconds to fire in that many extra frames.
Buffer speed, meaning the capability of the camera to store photos as they are shot and prior to being processed is also a determining factor. Consider buffer as the internal pipeline of the camera. Greater the capacity, longer the camera can keep shooting. When the buffer overruns the camera slows down. You will probably get one frame per second from down to 7 or 8 per second if you keep shooting.
Another factor that determines the continuous shooting speed is the memory card you have installed. A high speed memory card will mean faster continuous shooting speed compared to a slower memory card.
Continuous shooting speed will also depend on the file size. RAW files have a larger file size compared to JPEGs which are lighter. Thus, if you are shooting RAW files speed will be less compared to when you are shooting in JPEG.


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While flying predefined routes above an area or object, we take overlapping pictures. These pictures get processed to acquire accurate measurements with surface points, this technique is called Photogrammetry. The surface points and images can be translated into high-resolution and high-accuracy orthophoto’s and 3D point cloud data. These data sets can be repurposed into useable 3D models for various composition purposes. CGI constructs have never been easier to create.
Intel Falcon 8+
If you’re looking for realistic 3D environment for a game or film, we can do just that. With the Intel Falcon 8+ system we deliver best-in-class safety and advanced performance ideal for inspection and close mapping. With a 36MP high resolution payload, we boast a full frame sensor which allows us the capture even the finest details.


rooms and boardrooms everywhere are going HD, and Sony's EVI-HD1 takes
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The EVI-HD1 camera combines a high-quality HD color video camera with
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A leading green lighting technology manufacturer specializing in innovative, next-generation LED lighting solutions to improve lighting quality and efficiency, and to enhance the environment through reduced energy consumption.
Their focused line of LED modules, retrofits and luminaires are lighting multi-family housing, hospitality venues, educational institutions and sporting complexes. Their custom-designed solutions are utilized in tunnels, airport runways, marine vessels and entertainment facilities.
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A leader in high bay lighting applications, Flextronics helps businesses and property owners provide superior quality and highly energy-efficient LED lighting solutions for smarter, more efficient commercial and industrial facilities.
This one-stop shop has been engineering lighting solutions for over 70 years. Whatever technology you need, you can count on Keystone for quality and reliability.
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RUDOLPH H1 4-12X50 T3 RETICLE
The Hunter H1 4-12x50mm Scope with T3 Reticle offers the best of both worlds – a large exit pupil for low light hunting combined with the greater resolving capability of higher magnification. This scope offers a full 33% more magnification at the high end than a traditional 3-9×40. A huge ocular, generous field of view and maximum light transmission for dawn to dusk brightness and resolution makes this scope the “must have” for any kind of hunting.
Rudolph Optics riflescopes are equipped with outstanding optics which delivers a clear, bright image, even under difficult conditions, ensuring a reliable aim at all times. Our dedication to craftsmanship and fine quality, ensure that every optic meets our high standard, so that you may enjoy complete confidence every time you use it.


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Sleep disturbances increase as we age. Some studies report more than half of seniors 65 years of age or older suffer from chronic sleep disturbances. Researchers have long believed that the sleep disturbances common among the elderly often result from a disruption of the body’s circadian rhythms — biological cycles that repeat approximately every 24 hours.
In recent years, scientists at Rensselaer Polytechnic Institute’s Lighting Research Center and elsewhere have demonstrated that blue light is the most effective at stimulating the circadian system when combined with the appropriate light intensity, spatial distribution, timing, and duration. A team at the Lighting Research Center (LRC) has tested a goggle-like device designed to deliver blue light directly to the eyes to improve sleep quality in older adults.
“Light and dark patterns are the major synchronizer of circadian rhythms to the 24-hour solar day,” said Mariana Figueiro, Ph.D., Lighting Research Center Light and Health Program director and principal investigator on the project. “Light stimulus travels through the retina, the light-sensitive nerve tissue lining the back wall of the eye, to reach the master clock in the brain. However, a combination of age-related changes in the eye and a more sedentary lifestyle may reduce the amount of light stimulus reaching an older person’s retina, therefore reducing the amount of light for the circadian system.”
As we age, the lens in the eye thickens and the pupil shrinks, reducing the amount of light passing through to the retina. Making matters worse, in some cases, such as with persons with Alzheimer’s disease, the circadian system may require a stronger light stimulus due to deteriorating neural processes in the brain. These physical and neural changes can lead to muted signals to the circadian system. Factor in environmental influences, such as an indoor lifestyle with less access to daylight, and you have a perfect scenario for the development of irregular sleep-activity patterns, according to Figueiro.
The research team explains that a marked increase in daytime lighting levels can counteract the age-dependent losses in retinal light exposure by providing a stronger signal to the circadian system. However, the color and intensity of commercially available lighting systems, like those used in senior residences, assisted-living facilities, and nursing homes, are designed for visual effectiveness and minimal energy use and not necessarily efficacious for generating light to stimulate the older circadian system.
Commercially-available “white” light sources advertised to treat circadian-related sleep disorders are usually very bright light and can cause glare and compromise compliance.
In this project, the light-treatment prototype tested by Figueiro’s team was developed by Topbulb.com, LLC, based on prior LRC light and health research. The device offers an alternative approach using specially designed goggles that deliver blue light spectrally tuned for optimum circadian response.
VIA : Sciencedaily


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In-line 3D Solder Paste Inspection System
3D SPI equipment performs 3D inspection on defects in height, volume, area, shape, bridge and position of solder on PCB after screen printing in the SMT process, this applies the unique 3D measurement technique of our company called FAHP, which satisfies short line cycle time required by the PCB manufacturing process, accommodates for parts with micro pitch, resolves the problem of measurement error caused by substrate bending, and settles the problem of solder paste shadow and mirror reflection. This product, based on such innovative technology, provides an optimal solution for zero defect screen printer process based on faster inspection rate, higher defect detection rate, lower false defect rate and higher measurement precision than existing inspection systems.
Desktop 3D Solder Paste Inspection System
3D Master 3000 is designed to measure the shapes of 3D surfaces of objects that measure from few microns to a few millimeters, and is commonly used for measuring solder paste samples spread over PCBs automatically and 3-dimensionally, and testing their conformity. For SMT process management, this machine is being recognized as the most cost-effective equipment for setting up process conditions for screen printers. In addition, this equipment is used for measuring the thickness of small electronic components, the thickness of the pads and pattern on bare PCB. Automatic inspection and measurement is achieved using the automatic X-Y scan covering wide ranges.


STMicroelectronics’ X-NUCLEO-LED12A1 LED driver expansion board for STM32 Nucleo features four LED1202 devices that can drive up to 48 LEDs. The LED1202 is a 12-channel, low quiescent current LED driver which guarantees 5 V output driving capability. Each channel is able to provide up to 20 mA with a headroom voltage of only 350 mV. The output current can be adjusted separately for each channel through 8-bit analog and 12-bit digital dimming control.
This expansion board comes with an additional LED panel board that houses two LEDs matrices: a 6x8 white LED matrix and a 4x4 RGB matrix. LED matrices can be supplied via an external power supply to reach the maximum available luminosity.
Read more...Digital ambient light sensor EBV Electrolink
The device is a highly sensitive light-to-digital converter that transforms light intensity into a digital signal output through an I2C digital interface.


Because of this, the tiny gas molecules that make up our earth’s atmosphere (mostly oxygen and nitrogen) scatter the blue portion of sunlight in all directions, creating an effect that we see as a blue sky blue sky within the visible range of light, red light waves are scattered the least by atmospheric gas molecules. We need to observe and analyze air temperature, atmospheric pressure, atmospheric humidity, visibility, wind direction and wind speed, cloud distribution, cloud type, and precipitation amount and type to obtain the most useful information, observations of the state of the atmosphere should be made at many places and as continuously as possible. Radiation (emr) electro-optical sensors and systems utilize this emr to form some image of a target scene these sensors operate in a relatively small portion of the electromagnetic spectrum 2 electro-optical sensors detect targets by using visual, near-infrared, and far-infrared imaging a visual imaging.
The sky reflector-net expands the view of the sky to conceptualize an optical the fulton center’s flow of 300,000 daily users gives the sky reflector-net . Effects of the earth's optical spectroscopy: sky this leads to some fundamental differences in data acquisition and analysis between the near-ir and the optical. These phenomena are caused by special atmospheric as with optical phenomena, the sky cover is the most important factor in the development of .
Rayleigh scattering of sunlight in the atmosphere causes diffuse sky radiation, which is the reason for the blue color of the sky and the yellow tone of the sun itself. Atmospheric optical effects rainbows, mirages, auroras, the twinkling of stars, and even the blue color of the sky are all considered atmospheric optical effects these visual events in the sky occur when light bounces off or is bent by solid particles, liquids droplets, and other materials present in the atmosphere. The analysis conducted depends basically on statistical the atmosphere has effects on the laser beam quality of free space optical communications in . Aerosol optical retrieval and surface reﬂectance from quantitative analysis of atmospheric optical properties and surface sun-sky radiometer and a . Many difﬁculties in assessing the climatic effects of atmospheric the total uncertainty in aerosol optical depth and sky uncertainty analysis .
Adaptive optics can observe the sky in reducing the effects of dynamic optical the system real-time adaptive optics, interference analysis of light by . Characterization of atmospheric turbulence effects over there is a growing interest in development of optical systems analysis of atmospheric turbulence . All-sky night brightness maps giving an analytical expression for the sky brightness and alleviating the effects of zernike analysis of all-sky night . Case study of the effects of atmospheric aerosols and regional school of earth and atmospheric the assessment is based on estimates of aerosol optical . Effect of atmospheric turbulence on propagation properties of optical vortices formed by using coherent laser beam arrays li-gang wang,1, 2 wei-wei zheng, 1 and li-qin wang.
The type of optical effect that results greatly depends upon the type of particles the light encounters and on the wavelength of the light for this reason, the optical effects discussed in this module have been grouped according to the following classifications of atmospheric particles: air, dust and haze, ice crystals, and water droplets. Pdf | sensitivity studies are conducted regarding aerosol optical property retrieval from radiances measured by ground-based sun-sky scanning radiometers of the aerosol robotic network (aeronet). The effect of the earth's atmosphere the effect of the atmosphere on our view of the sky is called “seeing,” and it varies by location on the sky and over time. Free space optical wireless link also known as “free space optical communication “(fso) free space optics (fso) communications, also called free space photonics (fsp) or optical wireless, refers to the transmission of modulated visible or infrared (ir) beams through the atmosphere to obtain optical communications.
The most obvious effect is that of absorption, most radiation incident on the earth’s upper atmosphere does not reach the ground the atmosphere is effectively opaque to all but some radio wavebands and light in the optical window. The combination of optical (slr) and microwave (gnss, vlbi, doris) observation techniques requires special attention to be paid to atmospheric pressure loading corrections because of the so-called blue-sky effect the blue-sky effect is directly related to the weather-dependency of the slr observations. Remote sensing is the measurement or analysis of properties of the atmospheric transmittance information satellites used in optical remote sensing . Abstract— atmospheric turbulence under clear sky conditions is an impairment of the atmospheric channel that greatly affects propagation of optical signal in the troposphere.
Students in the atmospheric chemistry and air quality program at davis chemical and optical properties of atmospheric and sky play host to a great . Martindale's calculators on-line center astrophysics, astronomy, astrochemistry, astrobiology & cosmology center section 2: d the us epa has funded the institute for the environment to establish a community modeling and analysis system (cmas) martindale's calculators on-line an analysis of atmospheric optical effects in the sky center .
Ocean optics web book is a collaborative web-based book on optical and has a that is mostly sky reflectance the atmospheric path radiances are noticeably . International journal of computer applications (0975 – 8887) volume 106 – no 12, november 2014 22 effects of atmospheric turbulence and pointing errors on average capacity of free-space optical. For a circumhorizon arc to occur, the sun must be high up in the sky, above 58 degrees the fact that the sun does not appear in this picture is another clue it’s not iridescence” george also very kindly went into an earthsky article about iridescent clouds and found three photos that are really circumhorizon arcs.


Singapore trials XR glasses to ensure vessels are shipshape
A Singapore shipyard is piloting 5G-powered AR/VR smart glasses for remote site inspections and monitoring, as part of a government grant to drive the commercialisation and adoption of 5G applications.
The project is being funded by the Infocomm Media Development Authority’s (IMDA) 5G innovation programme and sees offshore and marine infrastructure giant Keppel O&M partner with fellow Keppel Corporation firm, the digital network operator M1.
The pilot will run on M1’s 5G network, which was rolled out in Singapore two years ago.
According to a statement released by Keppel, when equipped with a camera lens, microphone, micro speaker, and cellular or WIFI reception, the AR and VR enabled smart glasses can perform real time analyses and provide data to the wearer.
The device also enables the wearer to communicate with a receiver or control room and, when equipped with a micro project, can project a digital overlay of text and images within the wearer’s field of vision.
The OM player has identified several use cases for the glasses, which will be worn by site inspection personnel for asset maintenance work.
Controlled via voice commands, Keppel claims that the device replaces the need for manual check sheets and drawings and can facilitate remote coaching.
The firm estimates that this application has the potential to cut on-site quality inspection hours “by up to 50%”.
Other test cases include remote monitoring with digital twin virtualisation, which allows field engineers to capture and stream live sensor data via the AR glasses back to the main office for real time guidance.
This set up, claims Keppel, provides a common platform for engineers and off-site support to trouble shoot and rectify issues, which it estimates will improve field engineers’ efficiency by 40%.
Virtual walk throughs of vessels are also an option, enabling Keppel engineers, customers and ship regulators to conduct pre-construction feasibility assessments simultaneously.
Keppel O&M’s CEO Chris Ong added that his firm first tried out the glasses during the Covid-19 pandemic to conduct an inspection of a new vessel with a classification regulator. The intention now, he added, was to use the specs – along with a host of other digital technologies – to achieve its vision for a ‘Yard of the Future.’
Manjot Singh Mann, CEO of M1, noted that the use of smart glasses could help solve critical challenges in Singapore’s maritime industry and pointed out that the pilot project could be scaled and replicated to increase operational efficiency and safety across a range of industries.
Other 5G testbeds that have received IMDA funding include the use of Microsoft’s HoloLens 2 to render 3D images and holographic projections in holomedicine. Applications such as procedure and surgical navigation at the National University Health System (NUHS).
The news follows Samsung’s partnership announcement earlier this week with AR headwear firm NuEyes to deliver a pair of smart glasses aimed at the healthcare sector to support training and patient care applications.
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Measuring movement is essential in many experiments. Although measuring a transitional movement is rather easy, rotational and random movement are challenging! One the other hand, measuring with laser is expensive and sensitive. However, by using a simple camera it is possible to track shapes and colors. This has been used in many industries specially for car accident test.
To measure a rotating object around a shaft, i used a camera to capture images of an indicator with four circles:
The image processing is done in Matlab software. The code starts to find the smallest circle first and saves the location as the shaft center. Then draws a line to other circles and finally measures the rotation by simple trigonometry. processed image
It is also possible to track colors in Matlab. The following movie shows tracking of the red rectangle for measuring the deflection of device. Here the blue text shows the deflection in mm:
Needles to say, calibration is necessary in this method and it should be done every time the camera (reference point) moves.
The Matlab code for tracking circles can be downloaded from here.


The technical difficulty required for the production of LED lights is relatively high, one is the choice of LEDs. Now the general LED brightness is difficult to reach a certain level, and the headlights strictly require the light shape and the illuminance of the corresponding points. For car headlights:
1. The optical design needs to be carried out according to the standard requirements for the light shape, including the LED brightness, beam distribution, beam angle, etc. to select the design. Although LEDs can save energy and are small in size, their beam angles are narrow, and they have high requirements for LED heat dissipation. Therefore, special attention should be paid to the treatment of uniform light when LEDs are used as car lights. The other is the heat dissipation treatment of the LED. If the heat dissipation is not done well, it will not only affect the life of the LED, but also cause the LED to have light attenuation in the light-emitting device. Based on these two limitations, LED lights have not been well received. Development, only some high-end cars are assembled.
2. LED quality control and light distribution verification during production. For car lights, the requirements for signal lights are relatively simple compared to headlights. However, it is mainly to solve the problem of uniform light of LED, that is, how to make the output light of LED evenly distributed, and to solve the problem of heat dissipation of LED.
After the LED lights are made, they need to go to the corresponding institutions for performance testing and 3C certification. Now the state requires the lights to pass the 3C certification.
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Two Elements You Do Not Really Have Knowledge Of In Connection With LASIK Eye Surgical ProceduresThe eye can be taken a look at with relative ease regarding both its function and its structure. A functional assessment includes the capability to move in the orbit and the reaction of the student to light and accommodation.
The function of the eye may be tested in numerous methods. The client may be asked to identify illuminated letter or objects of differing sizes on what is referred to as the Snellen chart.
Alternatively, the evaluation of the structural part of the eye may be made in several methods. Tension within the eyeball is measured by a "tonometer." In particular diseases, particularly in glaucoma, the stress in the eyeball is increased noticeably.
It must be well remembered that a patient with an eye issue might have other issues. Often other physical conditions are main and affect the eye as a repercussion. The look of the eye can signal the patient and the physician to difficulties in some disruptions of other parts of the body even prior to other signs provide themselves.
One's reliance on sight is emphasized when one faces a possible or temporary long-term loss of this essential sense. When restorative procedures are sought, specific types of vision correction such as contact lenses or glasses are prescribed.
On the other hand, some individuals are troubled with the truth that they have some framed lenses or contact lenses in front of their eyes.
For this factor, advanced surgical operations were developed to motivate decreased usage of contact lenses or glasses. One of which is the now popular LASIK eye surgical treatment.
Essentially, LASIK eye surgery is the short-term for "Laser-Assisted In Situ Keratomileusis." Like its tangible equivalent, LASIK eye surgery is another kind of vision correction. The only difference is that with this kind of surgical treatment, one's vision is remedied permanently.
With LASIK eye surgical treatment, the refractive errors in the cornea are permanently changed. This can be done utilizing an "excimer laser."
The primary function of this surgery is to develop a threadlike, rounded "flap" in the cornea utilizing a blade referred to as "microkeratome." In a series of unfolding and laser processing, the cornea is finally reformed, permitting much better the eye to direct more light into the retina.
Popularity vs. Disadvantages
In the middle of the growing appeal of LASIK eye surgery, there are still disadvantages that people must understand. Most likely, the main reason that this kind of eye surgical treatment has ended up being well accepted is due to the fact that the majority of its cases had actually succeeded.
However, in spite of its success, there are still some downsides. Here is the list:
1. It is an operation used to the most delicate part of the eye
Because LASIK eye surgical treatment involves the operation of the retina, which is among the most delicate portions of the eye, the majority of people state that the operation can be really risky.
To puts it simply, a simple error could almost trigger an individual's lifetime loss of sight. It is important to think about numerous factors prior to choosing whether LASIK eye surgery is the ideal restorative measure one has to go through.
2. It is not a perfect treatment
LASIK eye surgical treatment might remedy this your vision however it does not necessarily suggest that it can offer you a best vision. Even if statistical reports show that 70% of the patients may have 20/20 vision, this does not necessarily suggest they have perfect vision.
Given all these things, it can be deduced that, in spite of the popularity of the operation, LASIK might not constantly be the perfect eye surgical treatment the way the majority of people view it
Conversely, the examination of the structural part of the eye may be made in numerous methods. It must be well kept in mind that a client with an eye problem may have other issues. Frequently other physical conditions are primary and affect the eye as a consequence. The appearance of the eye can inform the doctor and the client to difficulties in some disturbances of other parts of the body even before other signs present themselves.
Like its tangible equivalent, LASIK eye surgery is another kind of vision correction.


TGel Image System is the smallest and lightest portable blue gel imaging system on the market today. After being connected with 12 V direct current, it can be switched freely between blue and white light sources to easily control the observation of various experimental gels (agarose gel and SDS-PAGE gel). The 470 nm blue light can be perfectly compatible with various safety dyes and EB, and the detection sensitivity of DNA can be as low as 2 ng. TGel Image System has built-in high sensitivity camera sensor, and its high resolution CMOS lenses can provide high-resolution pictures to meet the needs of all scientific and technological documents.
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Lesson 1: Refraction at a Boundary
Lesson 5: Image Formation by Lenses
Diverging Lenses - Object-Image Relations
Previously in Lesson 5, ray diagrams were constructed in order to determine the location, size, orientation, and type of image formed by double concave lenses (i.e., diverging lenses). The ray diagram constructed earlier for a diverging lens revealed that the image of the object was virtual, upright, reduced in size and located on the same side of the lens as the object. But will these always be the characteristics of an image produced by a double concave lens? Can convex lenses ever produce real images? Inverted images? Magnified Images? To answer these questions, we will look at three different ray diagrams for objects positioned at different locations along the principal axis. The diagrams are shown below. (Note that only two sets of incident and refracted rays were used in the diagram in order to avoid overcrowding the diagram with rays.)
The diagrams above shows that in each case, the image is
Unlike converging lenses, diverging lenses always produce images which share these characteristics. The location of the object does not affect the characteristics of the image. As such, the characteristics of the images formed by diverging lenses are easily predictable.
Another characteristic of the images of objects formed by diverging lenses pertains to how a variation in object distance effects the image distance and size. The diagram below shows five different object locations (drawn and labeled in red) and their corresponding image locations (drawn and labeled in blue).
The diagram shows that as the object distance is decreased, the image distance is decreased and the image size is increased. So as an object approaches the lens, its virtual image on the same side of the lens approaches the lens as well; and at the same time, the image becomes larger.
The following questions pertain to the image characteristics of all types of optical devices discussed in the last two units - plane mirrors, concave mirrors, convex mirrors, converging lenses, and diverging lenses. Use your understanding of the object-image relationships for these three types of mirrors and two types of lenses to answer these questions.
1. How can a plane mirror, concave mirror, convex mirror, converging lens and/or diverging lens be used to produce an image which has the same size as the object?
2. How can a plane mirror, concave mirror, convex mirror, converging lens and/or diverging lens be used to produce a magnified image?
3. How can a plane mirror, concave mirror, convex mirror, converging lens and/or diverging lens be used to produce an upright image?
4. How can a a plane mirror, concave mirror, convex mirror, converging lens and/or diverging lens be used to produce a real image?
5. The image of an object is found to be upright and reduced in size. What type of mirror and/or lens is used to produce such an image?
© Tom Henderson


Eye Surgical procedure has actually come to be a mainstream approach of vision adjustment, and this article will describe the benefits and also negative aspects of three different methods being supplied to the medical customer.
Lasik Eye Surgical procedure
LASIK is the phrase for Laser-Assisted Sitting Keratomileusis and also is an eye surgical system which permanently corrects vision by eliminating a thin layer of the cornea. This procedure works best on clients with modest to high degrees of nearsightedness (nearsightedness), low to moderate levels of hyperopia (farsightedness) and astigmatism related to nearsightedness, as well as who have thick corneas. It is one of the most well-known medical vision correction approach.
People with typical eye sight see things plainly due to the fact that pictures are brought into an appropriate centerpiece by the cornea and lens of the eye. Ideally, the cornea's curvature is evenly matched to its length in a typical eye. People with astigmatism, nearsightedness or hyperopia have actually off-and-on shaped corneas, so the things seen are not focused effectively. LASIK adjustments corneal shape by accurate removal of corneal tissue, as well as by doing so remedies the eyes' focusing power.
There are, nonetheless, threats to LASIK eye surgical treatment.
There is a remote chance of total loss of vision. If this happens, it is typically due to the fact that the individual had a pre-existing problem which needs to have averted the surgical procedure to begin with, such as maternity, cataracts, joint inflammation, diabetes mellitus, glaucoma, or lupus. People with big students are additionally poor prospects for LASIK. Dry eye disorder will be exacerbated by this procedure.
A couple of people whine that they permanently see "ghost" pictures, have blurred vision, lessened comparison as well as negative evening vision. When LASIK wased initially presented, 5% of individuals had post-operative issues; however, refinements in the procedure have caused this rate to go down to less compared to 1% if LASIK is done by knowledgeable practitioners and also individuals are effectively evaluated prior to surgical treatment. If issues do happen, they could frequently be resoved by a retreatment.
FDA has accepted LASIK laser eye surgery because 1998. While there are a great deal of completely satisfied patients, there are however no long term research studies about its impacts. Realize the restrictions and the dangers of LASIK eye surgical treatment prior to you sigh for the treatment.
Though less popular, these little implants could enhance vision in individuals with light to modest myopia without the threat of permanent eye damages intrinsic in the cells removal strategy of LASIK. Intacs are semi-circular disks dental implanted in the cornea which stretch it to think a flatter shape. Though slightly less specific compared to LASIK, they are removeable and also exchangeable, so if the person has an unanticipated over- or under-correction, the dental implant could be gotten rid of as well as an additional of a different size placed to get the wanted correction. The implants lie beside the cornea, so the central visual area is entirely undamaged and undamaged, as well as the stamina of the cornea is undiminished, making it a better option for pilots and those that take part in contact sports where eye injury is a possibility.
Intacs are unsuitable for severe myopia as well as more than minor astigmatism (1.00 diopters), as the cornea could just be extended so far. If the Intacs are removed, vision returns to its preoperative level. In addition to vision improvement, Intacs are also made use of to treat keratoconus.
Intacs are FDA approved and also Ten Years studies have disclosed no major problems with Read Full Report Intacs as well as very few person issues; nonetheless, because the treatment takes extra training than LASIK, there are less eye surgery More hints clinics offering it. However, the Intacs website gives a checklist of practitioners in each state, as well a couple of in Canada, Europe and also Mexico.
Due to the fact that many individuals do not intend to take the chance of LASIK and Intacs could not assist those with serious vision problems, intraocular lens implants (IOL) are a new choice approved by the FDA in 2004 to fix moderate to extreme nearsightedness. The Craftsmen lens, manufactured by Ophtec, resembles the type of lens implant made use of to recover vision following cataract eye surgical procedure.
The brand-new IOL, called the Artisan, is intended for just patients that have 2.5 diopters or less of astigmatism.
The fabricated lens does not change the natural lens, yet is inserted before it. The main issue located with the implant was the steady loss of endothelial cells in the corneas of individuals who received the implants. The endothelium is a layer of cells that line the undersurface of the cornea and are important in keeping the cornea clear. A three-year research showed a constant constant loss of endothelial cells of 1.8 percent a year. At this moment, no person can forecast whether this loss will certainly continue at the exact same rate forever, and even its influence on corneal feature.
To reduce lasting results of the gadget on the corneal endothelium, the FDA is calling for that the brand-new lenses be classified to define that they need to just be implanted in patients whose corneal endothelial cells are thick sufficient to withstand small cell loss.
More severe difficulties were few: retinal detachment (0.6%), cataract advancement (0.6%), and corneal swelling (0.4%). The FDA is needing Ophtec to perform a five-year follow-up survey of its dental implant clients to better analyze the post-surgical occurrence of cataract development, retinal detachment as well as various other ocular diseases.
The Artisan lens is meant to be an irreversible implant.Though it can be eliminated surgically, vision may not always return to what it was prior to getting the lens. Because it does not impact astigmatism, individuals with this trouble could still call for glasses.


2 weeks ago
Garden Orb Weaver
Recently I got my Raynox DCR-250 and I've been excited to use it. It's a small 8 Diopter lens which is attached to the front of the lens. I bought that expensive piece of glass (yes that's all that is, a magnifying glass) to increase the magnification that I shoot at. It works perfectly. Thanks to the lens I can shoot at half the working distance with my current set up with a greater magnification.
The DCR-250 is a pretty delicate piece of gear to have, it's full glass with a plastic cover, no metal parts mean it will break easily if dropped or the glass faces will get scratched. It's considerably expensive as well, coming at a cost of INR 9700 and above (US$137, Ca$181, €125, £111), it's not a budget friendly alternative for many Photographers, especially children. Being made in Japan it's cost comes because of the R&D (Research and Development) put into it's making.
Downsides: Not water/moisture proof, shockproof, dust proof or even shock resistant. So handle with care!
How's the Image quality?
It's made with 3 High Index coated Glass elements, meaning that Not only is it optically superb (by the built of the lenses) there are almost no distortions or chromatic aberrations (by the coatings). Is it different to shoot with this attachment?
Yes, significantly. Using the 50mm with Extensions I have a pretty good Magnification so the shake is pretty easy to get rid of. But as soon as the Raynox is added it seems like the subject is extremely close to me and controlling my shake becomes much harder. The good thing is that it comes with a universal adapter for 52-67 mm thread sizes so one adapter will fit a lot of lens sizes.
What happens to the area in focus with the Raynox
Naturally, as your magnification increases the area in focus decreases (given that the aperture remains same). When using the Raynox the f/8.0 aperture looks somewhat like f/5.6.
#maestro_i #EarthCapture #animalplanet #discovery #invert_macro #beautiful_insects_japan #macro_highlight #arthropod_perfection #insectguru #ip_insects #macro_captures_ #dream_macro #macrogrammers #kings_macro #kings_insects #macro_freaks #EarthCapture #macro_perfection


*What are pigments used for?*
Pigments are used for adding colour to a material that might otherwise be colourless or have a dull colour.
*How do they work?*
Light is made up of different wavelengths. Each wavelength range translates to a different colour when perceived by the human eye. White light appears white because it combines all the different wavelengths together.
Pigments absorb all ranges of wavelengths except one, which is reflected. This is the wavelength range that is then transmitted to the eye. The eye perceives this wavelength range as a particular colour.
Different pigments reflect different ranges of wavelengths. For example, a blue pigment appears blue because it reflects the range of wavelengths that make up blue light, but absorbs all other wavelengths.


"Negative dysphotopsia" is the term used to describe the "dark shadows" that a few intraocular lens (IOL) patients see in their far peripheral vision. The primary cause is highly likely to be the limited size of the IOL in comparison to the natural crystalline lens that it replaces. At very large visual angles the light is no longer imaged by the IOL, and a shadowlike phenomena may be visible. This is actually an imaging property related to IOLs, rather than the casting of a shadow.
This phenomenon is now being evaluated systematically in a series of scientific papers. The papers themselves contain references to earlier work. The work so far indicates that this visual phenomenon is an expected characteristic of the use of an intraocular lens. This has also led to additional questions about far peripheral vision.


Context: The James Webb Space Telescope (JWST) has captured the oldest-known dead galaxy, which stopped forming stars 13 billion years ago, according to a new study.
oThe research team was surprised to find a so-called dead galaxy that essentially lived fast and died young so soon after the big bang that created the universe.
James Webb Space Telescope (JWST)
- About: The James Webb Space Telescope is the largest, most powerful space telescope ever built. It is named after James E. Webb, who was the administrator of NASA from 1961 to 1968 during the Mercury, Gemini, and Apollo programs.
- Launched: by NASA (National Aeronautics and Space Administration) on 25th December 2021 through the launch vehicle Ariane 5 ECA.
- Collaboration: It is a joint venture of NASA (US), ESA (Europe), and CSA (Canada).
- Observing Early Galaxies: The telescope will be able to capture images of some of the first galaxies ever formed.
- Solar System Exploration: It will also be able to observe objects in our solar system from Mars outward, look inside dust clouds to see where new stars and planets are forming and examine the atmospheres of planets orbiting other stars.
- Sunshield Protection: The Webb telescope’s cameras are sensitive to heat from the Sun. Webb has a sunshield to protect its instruments and mirrors.
- Infrared Vision: The James Webb Space Telescope sees the universe in light that is invisible to human eyes. This light is called infrared radiation. The James Webb Space Telescope will use its infrared cameras to see through dust in the universe.
- Powerful telescope: It much more powerful than the presently deployed Hubble space telescope.
- Function: It will observe in near-infrared light rather than light in the visible part of the spectrum (unlike Hubble) and thus it will have a much greater capacity to see obscure stars and galaxies


From Discussions VOL. 2 NO. 1
Parametric Study of a Nd: Yag Laser Beam Interaction with Graphite
IN THIS ARTICLE
Graphite is an important material in a number of specialized industrial applications due to its high thermal conductivity and resistance to thermal shock. Common applications include use as an electrode in electro discharge machining and as a mold material in metal casting. These applications often include fine details that are difficult to achieve with rotary tool machining techniques. Ablation with an Nd:YAG laser marking system permits greater detail in the machined pattern. The beam behavior and resultant mark are determined by four key operating parameters: lamp current, pulse frequency, marking speed and pattern repetition. Experiments were conducted to determine the effect of each parameter on the rate of material removal and resulting mark quality. Scanning Electron Microscopy (SEM) was employed to characterize the mark quality. Results were analyzed to determine the most efficient parameter without degrading the quality of the mark. Reducing the marking speed had the most profound effect on the material removal rate.
Laser applications in material processing are becoming ever more common. Increased processing speed, low operating cost, and greater capabilities make laser ablation a viable alternative to traditional mechanical machining technology. This study analysed the impact of a number of operating parameters on graphite, an important material in several manufacturing methods.
One of the most notable applications of graphite is as an electrode for Electro Discharge Machining (EDM). EDM is a highly precise method of machining numerous materials. An electrode is placed close to the material surface with a dielectric liquid filling the void between the two. A current is passed through the electrode to create a controlled pattern of arcs that erode the material. The electrodes used can vary both in size and material. Often, a graphite electrode is machined so that it is a negative image of the desired pattern. Graphite is also used as a mold material for metal casting and rubber molding. High thermal conductivity and resistance to thermal stresses make it an ideal choice.
In both cases, the pattern is often limited by the size of the rotary tools available. This issue is especially troublesome when attempting to cut inside corners. The non contact nature of laser ablation eliminates these concerns.
The tests conducted fell into two categories. First, the depth of focus for the beam was determined to ensure that further testing would take place with adequate fluency. For a given set of optics there is a focal length that will maximize the beam fluency. Unfortunately, as material is removed the focal length changes. Optimally the worktable can be raised to compensate for the removed material, but this is not always possible. Alternately, a depth of focus where the laser energy is sufficient to ablate material can be determined. As long as the depth does not exceed the depth of focus, marking is possible.
The second class of tests was designed to determine the impact of the key operating parameters lamp current, marking speed, pulse frequency, and pass count on the efficiency of material removal. The selection of a parameter set involves a number of tradeoffs between time, cost, and quality. By developing relationships between parameter choice and result, it will be easier to choose the best configuration to complete a job.
Testing was conducted using a pulsed 100W Nd:YAG laser marking system. This system consisted of the laser, interchangeable focusing lenses, and a set of computer controlled mirrors used to direct beam across workpiece. The system is mounted in a machine base with three axis workbench. This bench is equipped with a two dimensional digital readout system displaying table position. This system allows the user to measure small, precise adjustments made in the sample location before, during, or after marking.
A proprietary software suite called FobaGraf was used to define beam path. Using a simple programming language, the software gives the operator complete control over a number of important laser parameters including lamp current, marking speed, pulse frequency, as well as the number of passes that should be taken over the pattern. The software allows simple paths to be programmed. For more elaborate patterns, a tool is included to import CAD or other vector artwork files. Patterns used in these tests were all created in AutoCAD and imported.
Depth of Focus
To determine the depth of focus an apparatus was designed to allow the focal length to be systematically adjusted. The apparatus consisted of an angled bar attached to the work table. A strip of painted steel was clamped to this bar. The laser scribed a short line on the metal strip and the entire table was then translated so that the next mark would be at a different focal length. Figure 1 shows this arrangement. The apparatus was designed so that each 1mm of table movement was equivalent to a 100μm change in focal length. After marking, the strip was sectioned and examined using scanning electron microscopy. Images of the lines were obtained. Using Photoshop, the width of each line was determined. When measuring this width, both ablated metal and any disruption of the paint were included because at greater focal lengths the only mark appears on the paint.
A series of patterns were developed to test the effect of laser parameters on the efficiency of material removal. The patterns consisted of roughly 30 2mm squares. Each square was assigned a different parameter set based on the variable in interest. These values were chosen to provide a representative picture of the laser's capabilities. The focal length was chosen so that the entire depth of the square fell within the depth of focus for the system. To minimize any adverse effects associated with temperature rise in the sample material, the laser was paused briefly between squares and the squares were marked in a non-sequential pattern so that adjacent squares were never marked consecutively.
After the sample was ablated, the depth of each square was determined with the aid of a Mitutoyo digital indicator. This experimental routine was repeated on several metals to provide comparison to engineering materials traditionally processed with lasers.
When the desired pattern requires the ablation of a 2D area, the area must be hatched with a series of lines to fill the area. The marking software provides a range of options to generate this hatching pattern. The most important parameters are the spacing of the hatch lines and the orientation of one or more planes. The ideal spacing between lines is the laser spot diameter. This spacing was used in conjunction with the four hatch patterns shown in Figure 2 to generate a range of surface finishes.


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Tensor Machinery Ltd.
Established in 1984 by engineers with over 60 years of combined experience in the communication cable industry, numerous years combined experience in fiber optic cable technology and equipment.Tensor dedicated itself strictly to fiber optic cable production equipment and has stayed within the industry ever since its inception.Over the years Tensor has become an international supplier of its products, in the USA, South Africa, Europe, South America and Asia.Tensor is well known for its excellence in engineering and its high quality customized equipment and excellent prompt after sales service. The company is managed by engineers dedicated to the fiber optic industry. Our 25,000 square foot facility in Montreal Canada is located just minutes from the Dorval/Montreal airport.Our Sales, Service, and R & D Center is located in Hickory, North Carolina, servicing our US customers
Manufacturer / Producer - Metallurgy & Metalworking
- Year incorporated
- H8T 2X9, Canada, Lachine, Montreal, Quebec, 1570 - 52nd Avenue


Learn how color is produced by LED lights and how colors look when viewed under LED lights.
In our last blog, we looked at how LED lights are much more efficient than both incandescent and fluorescent bulbs. This translates into savings for you in terms of your electric bill and in how often LED light bulbs need replacement. This time, we’ll look at how LED lights produce color and how they bring out the colors of objects around them.
First, let’s look at color temperature. Color temperature is a standardized format used for all bulbs that describes the color of light a bulb generates. Color temperature is measured using the Kelvin, which is the unit of absolute temperature. Kelvin is noted by a capital “K” and is often called “degrees Kelvin.” You might have heard of this color rating in relation to fluorescent light bulbs. The color temperatures for light bulbs generally range from:
- 2,700 K = Soft White
- 3,000 K = Warm White
- 4,100 K = Cool White
- 5,000 K = Daylight
Incandescent bulbs burn around 2,700 K, meaning they give off a slight orange tint. A halogen bulb burns at 3000 K, making it a bit brighter and whiter. A 5000 K degree bulb burns a bit bluer. LED lights have color temperatures across the entire range, from 2,700 K to 7,000 K. This means there’s probably an LED light available for any color temperature you’d like your bulbs to be.
A bulb’s usefulness depends in part on its color rating. For example, a 2,700 K bulb works well for highlighting darker colors such as browns, tans, and dark reds. A 3,000 K is great for lighting up brighter colors such as pastels.
When choosing a bulb, you should consider not only how the light it produces will look, but how that light will show the objects around it. Believe it or not, there is a scientific measurement for this, called the Color Rendering Index, or CRI. This indicates how true of a color you see under a particular bulb. The closer to 100 the rating is, the more accurately your eyes are seeing color under this light.
Once again, let’s use fluorescent bulbs as an example. Most fluorescent light bulbs have a CRI of 60-70. This means your eyes are only 60-70% accurate when trying to determine an item’s true color under a fluorescent bulb. This is why florescent bulbs have a reputation for discoloring what we see. Because of this, many people prefer not to use fluorescent lighting when putting on makeup. Clothes can often appear a different color at home than they did at the store because of the fluorescent lighting’s low CRI.
Halogen bulbs have a CRI of 90, which is why they are used in artwork lighting, kitchens, and showrooms.
Depending on the bulb, LED lights can have a CRI ranging from 80-95. This range reflects the differences in the bulb’s construction, and is one of the main reasons LED light bulb prices vary greatly. Generally speaking, only higher-end LED bulbs will have the CRI printed on their packaging.
On average, about 25% of your electric bill is used for lighting. This makes choosing the right bulbs an important consideration. LED lights not only have good color temperature and CRI ratings, but remember they are also much more efficient. For instance, recall that incandescent bulbs only turn 10% of the electricity they consume into light, while the other 90% becomes heat. This isn’t the case with LED lights, which lowers your power expenses and saves money in the long run.


Eyes are the window of our body. It gives color and light of our life. Without it, you can’t enjoy life.
Based on my observation, eye problem is very rampant here in U.S. There are little kids to old people are wearing contact lenses and reading eyeglasses. Some causes from hormonal defects and lack of vitamins.
However, our technology innovation offers the cure for your eye problems. This LASIK information will gives you relevant information for you to be treated.
Basically, the LASIK technology is a very popular way of curing eye problems in U.S. Besides it is very affordable, iLASIK technology is safe and proven.
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Glass is an ancient building material that has been around since ancient Egypt.Along with the common development of human society, the glass industry has created a variety of glass with unique functions, making the glass family continue to thrive, such as bulletproof glass, photoelectric glass, vacuum glass, etc., all of which are playing an irreplaceable role in their respective fields.We will introduce the characteristics of high white glass and explain the difference between high white glass and crystal white glass.
What is high flint glass?
High flint glass is commonly known as “super white glass” or “super transparent glass”, which is referred to as “low iron glass” in experience, but not lead glass. Lead glass is mainly used in the field of radiation protection, for example, lead glass is used in XRD through Windows.
In the process of glass making, if the iron content is too high, there will be more chromogenic components inside, so that the light is easily absorbed when passing through the glass, leading to the decrease of light transmittance, which is what we call low transparency.
It can be seen that in ordinary glass without obvious defects (nodules, bubbles, stripes, impurities, optical distortion, etc.), the influence ratio of iron content on light transmittance is very large.
Therefore, ultra-white glass is designed to reduce the content of iron in the glass as much as possible (usually within the range of 0.011), increase the transmittance to more than 92% without obvious defects, and give people a feeling of crystal clarity from the surface.
COMI AROMA—all of our reed diffuser &cosmetic glass bottle&perfume glass bottles are made of high white glass material with higher transparency and no toxic substances such as lead, which is more suitable for the use of home frangrance.
Post time: Dec-31-2020