Lens · prime
SMC Pentax-M 50mm f/2
Pentax · 1979-1985
Vintage35mm
Pentax's most compact 50mm lens. The f/2 aperture offers a middle ground between the f/1.7 and f/1.4 versions. Extremely light and small. SMC Pentax-M 50mm f/2: 5 elements in 5 groups, 6 aperture blades, 0.45m minimum focus, 49mm filter thread, 160g.
- Focal length
- 50mm
- Max aperture
- f/2
- Mount
- Pentax K
- Format
- 35mm
- Elements / groups
- 5 / 5
Known for
- General photography
- Travel
- Compact kit
- Learning
Considerations
- Slower than f/1.7
- Some versions have plastic parts
Optical characteristics
Silverlog's editorial rating: our own judgement, not measured data.
Sharpness (wide)4, level 4 of 5
Sharpness (stopped)5, level 5 of 5
Contrast5, level 5 of 5
Flare resistance5, level 5 of 5
CA control4, level 4 of 5
Vignetting control4, level 4 of 5
Distortion control5, level 5 of 5
Bokeh: Pleasant rendering
Rendering: Clean, modern
Colour: Neutral
Silverlog's editorial rating, 1 to 5; five is best. Not lab-measured.
Common issues
- Focus ring wear
- Plastic aperture ring on some
Buying guide
Less common than f/1.7. Check for metal vs plastic aperture ring. Good compact option.
Specifications
| Mount | Pentax K |
| Focal Length | 50mm |
| Max Aperture | f/2 |
| Min Aperture | f/22 |
| Aperture Blades | 6 |
| Min Focus | 0.45m |
| Filter Size | 49mm |
| Weight | 160g |
Optical design
| Formula | Double Gauss |
| Elements | 5 |
| Groups | 5 |
| Coating | SMC (Pentax) |
Pricing
- Typical used price
- £35 - £70
- Mint
- ~£100
Indicative, no dated source.