What to keep an eye on when purchasing a new optic to get the most out of it ...

An curved arrow pointing right. The lens on your camera can affect how you appear in photos. Follow BI Video: On Twitter More from Tech The lens on your camera can affect how you appear in photos.

You can use this effect artistically to blur out distracting ... The distance between the principal focal point and the lens is the focal length. So a 14mm lens bends light so it converges 14mm ...

A progressive lens design is like a bi- or tri-focal lens in that it corrects more than one vision problem at a time. However, these lenses have no visible lines, improving the cosmetic appearance of ...

The ideal astrophotography lens has an aperture of f/2.8 or less and a focal length of 20mm or less. These lenses are often larger than standard lenses, heavier, and pricer—typically due to the ...

Choosing an ideal lens shape -- known as the application's "best form" -- is key to minimizing optical distortion and aberration. Focal Length, Conjugate Ratio, and Lens Selection A lens's focal point ...

To minimize the effect of different lens' focusing speed, we test AF-active shutter lag with the lens already set to the correct focal distance. We also use the same Sigma 70mm f/2.8 macro with ...