Based on a classic design from 1952, the silver C Biogon T* 21mm f/4.5 ZM from ZEISS is a super wide-angle prime for M-mount rangefinder cameras. Its 'C' designation reflects the lens's compact form factor and classic optical design to produce imagery with true color fidelity and natural rendering. The Biogon optical concept helps to ensure virtually no distortion, and this eight elements, six groups layout also maintains a high degree of sharpness and clarity. Additionally, a T* anti-reflective coating has also been applied to reduce lens flare and ghosting for improved contrast in strong lighting conditions.