Comparison
KMZ Jupiter-8 50mm f/2 vs Pentacon auto 50mm f/1.8
The KMZ Jupiter-8 50mm f/2 is a 50mm f/2 M39 (Leica screw) lens made 1950s-1980s, valued at $30 to $120 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 | KMZ Jupiter-8 50mm f/2 | Pentacon auto 50mm f/1.8 |
|---|---|---|
| Focal length | 50 mm | 50 mm |
| Maximum aperture | f/2 | f/1.8 |
| Native mount | M39 (Leica screw) | M42 |
| Production years | 1950s-1980s | 1960s-1990 |
| Optical design | 6 elements / 3 groups, Sonnar | 6 elements / 5 groups, Double Gauss (Meyer Oreston derivative) |
| Typical used value | $60 | $45 |
| Value range | $30 to $120 | $20 to $90 |
| Adapts to | Sony E, Fuji X, MFT, Canon RF, Nikon Z, L-mount | 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 $60, a gap of $15. Ranges: $20 to $90 versus $30 to $120.
- Both are 50mm lenses, so framing is identical on the same sensor.
- The KMZ Jupiter-8 50mm f/2 is the older design; production began around 1950 against 1960 for the Pentacon auto 50mm f/1.8 (1950s-1980s versus 1960s-1990).
- They use different mounts, M39 (Leica screw) and M42, so each needs its own adapter. Both reach infinity on mirrorless bodies with a plain mechanical adapter.
- Construction differs: 6 elements in 3 groups for the KMZ Jupiter-8 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 $15 lower typical price, and the KMZ Jupiter-8 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.