Comparison
Nikon Nikkor 50mm f/1.2 AI-S vs Pentax SMC Pentax 50mm f/1.2
The Nikon Nikkor 50mm f/1.2 AI-S is a 50mm f/1.2 Nikon F (AI-S) lens made 1981-2020s, valued at $400 to $950 used. The Pentax SMC Pentax 50mm f/1.2 is a 50mm f/1.2 Pentax K lens made 1975-1990s, valued at $300 to $800 used.
Specifications side by side
| Specification | Nikon Nikkor 50mm f/1.2 AI-S | Pentax SMC Pentax 50mm f/1.2 |
|---|---|---|
| Focal length | 50 mm | 50 mm |
| Maximum aperture | f/1.2 | f/1.2 |
| Native mount | Nikon F (AI-S) | Pentax K |
| Production years | 1981-2020s | 1975-1990s |
| Optical design | 7 elements / 6 groups, Double Gauss | 7 elements / 6 groups, Double Gauss |
| Typical used value | $600 | $480 |
| Value range | $400 to $950 | $300 to $800 |
| 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
- Both open to f/1.2, so neither has a speed advantage.
- The Pentax SMC Pentax 50mm f/1.2 is cheaper. Typical used value is $480 against $600, a gap of $120. Ranges: $300 to $800 versus $400 to $950.
- Both are 50mm lenses, so framing is identical on the same sensor.
- The Pentax SMC Pentax 50mm f/1.2 is the older design; production began around 1975 against 1981 for the Nikon Nikkor 50mm f/1.2 AI-S (1975-1990s versus 1981-2020s).
- They use different mounts, Nikon F (AI-S) and Pentax K, so each needs its own adapter. Both reach infinity on mirrorless bodies with a plain mechanical adapter.
- Both use 7 elements in 6 groups.
Which one to buy
On the catalog data the Pentax SMC Pentax 50mm f/1.2 wins on the $120 lower typical price, and the Nikon Nikkor 50mm f/1.2 AI-S 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.