Cine lens

Stills lenses are designed to be autofocused and shot in single frames. Cine glass assumes a human pulling focus, so the focus ring has a long throw with hard stops at each end, the aperture ring is stepless for changes mid-shot, and both carry standard gear teeth for a follow focus. Aperture is marked in T-stops, which measure light actually transmitted rather than the geometric f-number, so two different lenses set to T2.8 match each other in exposure. A shared front diameter across a set means one matte box and one filter size. The cost is weight, price and no autofocus at all, and a solo creator working alone is usually better served by fast stills primes.