Production
1971 – 1975
Country
Japan
Optical
7 elements in 6 groups (Planar type)
Updated
Feb 15, 2026
Pentax SMC Pentax K 50mm f/1.2
Pentax K
Overview
The SMC Pentax K 50mm f/1.2 is Pentax's fastest 50mm — a rare and desirable lens that represents the peak of their manual focus era. With f/1.2 speed and SMC coating, it delivers a unique combination of light-gathering and optical quality.
Verdict: Pentax's crown jewel 50mm. If you shoot Pentax K mount and want the best, this is it. Rare but worth the hunt.
Optical Character
Bokeh
The bokeh is both smooth and busy, with a swirly, painterly quality, but is negatively affected by chromatic aberration.
Color
Pentax SMC lenses are well known for producing saturated, high contrast images.
Sharpness wide open
The lens is just about usable wide open, but does not perform well in terms of sharpness at its maximum aperture.
Flare resistance
The flares produced by the Pentax-A SMC 50mm F1.2 are not exceptional, but it still has a vintage feel.
Contrast
The lens produces higher contrast images than many vintage alternatives, even wide open.
Community Insights
Summary: The Pentax-A SMC 50mm F1.2 lens is a vintage lens that divides opinion among users. It has a solid, metal build and produces high-contrast, saturated images, though this can be both a positive and negative depending on the desired look. The lens struggles with chromatic aberration and sharpness when wide open, which some find disappointing given the premium price tag. Sentiment: Mixed Top Praised: - Solid, metal build quality - Smooth focus ring with 200° rotation, good for video - Produces high-contrast, saturated images Top Complaints: - Expensive compared to other vintage 50mm F1.2 lenses - Noticeable chromatic aberration, especially wide open - Mediocre sharpness performance when wide open Use Cases: - Portraits and low-light photography - Video work where the manual focus ring is beneficial - Matching the high-contrast look to certain modern lenses Disagreements: - Some users find the high-contrast look positive, while others see it as a drawback Confidence: 4/5 (the sources provide a fairly comprehensive and consistent overview of user experiences with the lens)
What people love
- f/1.2 speed
- Beautiful bokeh
- SMC coating
- Rare and collectible
- Pentax build quality
What people dislike
- Expensive ($400-700)
- Rare and hard to find
- Heavy
- f/1.2 DoF is challenging
Sample Photos
Sources (2)
vintagelensesforvideo-
https://www.vintagelensesforvideo.com/pentax-a-smc-50mm-f1-2-review/
Lens Heritage 2nd JSONsecondary
The SMC Pentax K 50mm f/1.2 is Pentax's fastest 50mm — a rare and desirable lens that represents the peak of their manual focus era. With f/1.2 speed and SMC coating, it delivers a unique combination of light-gathering and optical quality.