Carl Zeiss Distagon T* 28mm f/2.8 (C/Y) vs KMZ Mir-1 37mm f/2.8

What actually differs

• Both open to f/2.8, so neither has a speed advantage.
• The KMZ Mir-1 37mm f/2.8 is cheaper. Typical used value is $80 against $320, a gap of $240 (roughly 4x). Ranges: $40 to $160 versus $180 to $550.
• The KMZ Mir-1 37mm f/2.8 is longer at 37mm against 28mm, a 9mm difference that tightens framing slightly and increases background magnification.
• The KMZ Mir-1 37mm f/2.8 is the older design; production began around 1954 against 1975 for the Carl Zeiss Distagon T* 28mm f/2.8 (C/Y) (1954-1980s versus 1975-2005).
• They use different mounts, Contax/Yashica and M42, so each needs its own adapter. Both reach infinity on mirrorless bodies with a plain mechanical adapter.
• Construction differs: 7 elements in 7 groups for the Carl Zeiss Distagon T* 28mm f/2.8 (C/Y), 6 elements in 5 groups for the KMZ Mir-1 37mm f/2.8.

Which one to buy

On the catalog data the KMZ Mir-1 37mm f/2.8 wins on the $240 lower typical price, and the Carl Zeiss Distagon T* 28mm f/2.8 (C/Y) gives up nothing measurable in return except its own rendering, described below. Condition and variant matter more than the spec sheet at these prices.

Minimum focus distance, weight, and measured sharpness are not in the catalog, so this comparison does not claim anything about them.