query: What does it mean speed of lens in analogue photography?
positive_passages.docid: 20086
positive_passages.text: Why is the amount of light a lens lets in called the 'lens speed'?
negative_passages.docid: 109692
negative_passages.text: How does a spherical lens differ from an aspherical lens?
negative_passages.docid: 145622
negative_passages.text: How do constant aperture zoom lenses work?
negative_passages.docid: 20439
negative_passages.text: Do lenses have focal planes or focal spheres/ellipsoids?
negative_passages.docid: 128590
negative_passages.text: Is the formula for object image size given focal length, etc. independent of sensor size?
negative_passages.docid: 101736
negative_passages.text: What is the difference between Canon "L" lenses and non-L lenses?
negative_passages.docid: 11096
negative_passages.text: Why does my aperture setting change as I zoom on my DSLR kit lens?
negative_passages.docid: 88406
negative_passages.text: What does different focal length offer me?
negative_passages.docid: 150525
negative_passages.text: What is the difference between a telephoto lens and a zoom lens?
negative_passages.docid: 141771
negative_passages.text: What is the benefit of a wide-aperture lens if you stop it down?
negative_passages.docid: 8367
negative_passages.text: What do physicists mean when they say "speed of light"?
negative_passages.docid: 2224
negative_passages.text: What's the difference between using a 50mm f/1.8G and a 50mm f/1.8D with a Nikon D80?
negative_passages.docid: 27453
negative_passages.text: Simple explanation of relation between speed of sound and r.m.s. speed?
negative_passages.docid: 41934
negative_passages.text: How do zoom, magnification, and focal length relate?
negative_passages.docid: 97032
negative_passages.text: Does light accelerate or slow down during reflection?
negative_passages.docid: 38712
negative_passages.text: Diffraction by a lens
negative_passages.docid: 107952
negative_passages.text: Do different lenses affect noise level?