You can have the best camera for beginners, but if you don't truly understand focal length, you'll struggle to pick the right ...

Find out more about how we test. Focal length is the distance in millimetres from the imaging surface (film or sensor) and the optical centre of the lens when it is focused at infinity.

The F-number of a photographic lens is a measure of its light-gathering ability, and is expressed as its aperture diameter divided by its focal length ... components of a compound lens like ...

Herein, we demonstrate liquid compound micro-lenses with dynamically ... performance of the imaging device 55. Liquid lenses with variable focal length could form the basis of adaptive micro ...

Fantastic sharpness, great wide maximum aperture and lightweight design make this a truly ideal astrophotography lens.

However, lenses aren’t measured by perspective or by angle of view—they’re categorized by focal length, the distance between the center of the lens and the surface on which the image will be ...

while a telephoto focal length can give a more flattering result. While using a nice fast, prime lens is desirable, they do come at a cost and it's important to remember that you can achieve ...

Back in the days of yesteryear, when I bought my first single-len reflex, cameras came with single-focal-length lenses. Usually you started out with a lens of about 50 millimeters, because that ...