We may earn revenue from the products available on this page and participate in affiliate programs. Learn more › Believe it. Adoram’s ProOptic 500mm f/6.3 ($160, direct; adorama.com) shares all the ...

Researchers have combined theory and practice in a step-by-step method that eliminates much of the guesswork of using freeform lenses. Lenses and mirrors with freeform surfaces enable designers to ...

The technical definition of a telephoto lens is one with a focal length greater (or longer) than 50mm (on the 35mm/full frame forma), but the telephoto range is more generally accepted to begin at ...