query: How big a lens would you need to light a fire with moonlight?
positive_passages.docid: 81797
positive_passages.text: Is it possible to start fire using moonlight?
negative_passages.docid: 70023
negative_passages.text: A black torch to darken everything
negative_passages.docid: 87470
negative_passages.text: Is it reasonable to use a ring flash that encircles the lens for non-macro (general) shots?
negative_passages.docid: 52368
negative_passages.text: Does the diameter of the aperture increase with increases in the focal length with constant F-number(F-stops)?
negative_passages.docid: 116792
negative_passages.text: Is there a single lens suited for flying birds, mountains, and close-up portraits?
negative_passages.docid: 147042
negative_passages.text: The refraction through hot air around a candle flame
negative_passages.docid: 153779
negative_passages.text: Can I photograph a solar eclipse using a 10-stop Big Stopper (+ extra ND?)
negative_passages.docid: 31046
negative_passages.text: How much iron would I have to shoot into the Sun to blow it up?
negative_passages.docid: 11197
negative_passages.text: How do I convert lens focal length (mm) to x-times optical zoom?
negative_passages.docid: 58074
negative_passages.text: Physics of Focusing a Laser
negative_passages.docid: 116212
negative_passages.text: Taking a skyline photo with a person closer to the camera during night time
negative_passages.docid: 134627
negative_passages.text: How to photograph sparkly objects?
negative_passages.docid: 30788
negative_passages.text: Is the camera sensor or the lens the limit to resolution?
negative_passages.docid: 153578
negative_passages.text: Variable focal length for macro lenses?
negative_passages.docid: 95190
negative_passages.text: What should I look for in lenses for long range and close up animal and natural shots?
negative_passages.docid: 98701
negative_passages.text: If a lens focuses all incoming light to a point, how do we get 2D images?
negative_passages.docid: 57370
negative_passages.text: What are the limitations of a typical kit lens as a general purpose lens?