Comparison
Leica Summicron-R 50mm f/2 vs Pentacon auto 50mm f/1.8
The Leica Summicron-R 50mm f/2 is a 50mm f/2 Leica R lens made 1964-2009, valued at $350 to $900 used. The Pentacon auto 50mm f/1.8 is a 50mm f/1.8 M42 lens made 1960s-1990, valued at $20 to $90 used.
Specifications side by side
| Specification | Leica Summicron-R 50mm f/2 | Pentacon auto 50mm f/1.8 |
|---|---|---|
| Focal length | 50 mm | 50 mm |
| Maximum aperture | f/2 | f/1.8 |
| Native mount | Leica R | M42 |
| Production years | 1964-2009 | 1960s-1990 |
| Optical design | 6 elements / 4 groups, Double Gauss | 6 elements / 5 groups, Double Gauss (Meyer Oreston derivative) |
| Typical used value | $550 | $45 |
| Value range | $350 to $900 | $20 to $90 |
| Adapts to | Sony E, Canon RF, Nikon Z, L-mount, Fuji X, MFT | Sony E, Fuji X, MFT, Canon RF, Nikon Z, L-mount |
What actually differs
- The Pentacon auto 50mm f/1.8 is 0.3 stops faster: f/1.8 against f/2.
- The Pentacon auto 50mm f/1.8 is cheaper. Typical used value is $45 against $550, a gap of $505 (roughly 12.2x). Ranges: $20 to $90 versus $350 to $900.
- Both are 50mm lenses, so framing is identical on the same sensor.
- The Pentacon auto 50mm f/1.8 is the older design; production began around 1960 against 1964 for the Leica Summicron-R 50mm f/2 (1960s-1990 versus 1964-2009).
- They use different mounts, Leica R and M42, so each needs its own adapter. Both reach infinity on mirrorless bodies with a plain mechanical adapter.
- Construction differs: 6 elements in 4 groups for the Leica Summicron-R 50mm f/2, 6 elements in 5 groups for the Pentacon auto 50mm f/1.8.
Which one to buy
On the catalog data the Pentacon auto 50mm f/1.8 wins on the 0.3 stops of extra speed and the $505 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.