[…] stands for "apochromatically corrected". In most lenses, optical design concentrates the focus of blue light and green light into a single plane, but red light falls slightly into anot [..]

[…] stands for "aspheric design". Most lenses have a spherical design - that is, the radius of curvature is constant. These are easy to manufacture by grinding while "spinning" t [..]

What happens to light when it moves through R series Leica SLR bodies. Light from the lens is split into two when it hits the reflex mirror — one portion goes through the semi-silvered mirror to the l [..]

An acronym for "(C)lean, (L)ubricate & (A)djust

Refers to the maximum lens aperture — here ƒ3.5

Refers to the maximum lens aperture — here ƒ2.8

Refers to the maximum lens aperture — usually ƒ2.5

A compound word derived from "(Lei)tz

(As in "M3", "M6", "M7" etc.)

Refers to the maximum lens aperture — here ƒ1.0