Lens · prime
SMC Pentax-M 50mm f/1.7
Pentax · 1977-1984
Vintage35mm
SMC Pentax-M 50mm f/1.7: 6 elements in 5 groups, 6 aperture blades, 0.45m minimum focus, 49mm filter thread, 185g.
- Focal length
- 50mm
- Max aperture
- f/1.7
- Mount
- Pentax K
- Format
- 35mm
- Elements / groups
- 6 / 5
Known for
- General photography
- Portraits
- Street photography
- Learning manual focus
Considerations
- 6 aperture blades
- Not as fast as f/1.4
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: Smooth, pleasant rendering
Rendering: Classic Pentax character
Colour: Neutral with good saturation
Silverlog's editorial rating, 1 to 5; five is best. Not lab-measured.
Common issues
- Focus ring stiffness
- Sticky aperture blades
Buying guide
Check aperture operation and focus smoothness.
Specifications
| Mount | Pentax K |
| Focal Length | 50mm |
| Max Aperture | f/1.7 |
| Min Aperture | f/22 |
| Aperture Blades | 6 |
| Min Focus | 0.45m |
| Filter Size | 49mm |
| Weight | 185g |
Optical design
| Formula | Double Gauss |
| Elements | 6 |
| Groups | 5 |
| Coating | SMC (Pentax) |
Pricing
- Typical used price
- £25 - £60
- Mint
- ~£90
Indicative, no dated source.