Carl Zeiss Planar T* 50mm f/1.4 (C/Y) vs Leica Summicron-R 50mm f/2

What actually differs

• The Carl Zeiss Planar T* 50mm f/1.4 (C/Y) is 1 stop faster: f/1.4 against f/2.
• The Carl Zeiss Planar T* 50mm f/1.4 (C/Y) is cheaper. Typical used value is $220 against $550, a gap of $330 (roughly 2.5x). Ranges: $120 to $420 versus $350 to $900.
• Both are 50mm lenses, so framing is identical on the same sensor.
• The Leica Summicron-R 50mm f/2 is the older design; production began around 1964 against 1975 for the Carl Zeiss Planar T* 50mm f/1.4 (C/Y) (1964-2009 versus 1975-2005).
• They use different mounts, Contax/Yashica and Leica R, so each needs its own adapter. Both reach infinity on mirrorless bodies with a plain mechanical adapter.
• Construction differs: 7 elements in 6 groups for the Carl Zeiss Planar T* 50mm f/1.4 (C/Y), 6 elements in 4 groups for the Leica Summicron-R 50mm f/2.

Which one to buy

On the catalog data the Carl Zeiss Planar T* 50mm f/1.4 (C/Y) wins on the 1 stop of extra speed and the $330 lower typical price, and the Leica Summicron-R 50mm f/2 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.