Lens · prime
SMC Pentax-M 100mm f/2.8
Pentax · 1977-1984
Vintage35mm
Pentax's compact short telephoto. SMC Pentax-M 100mm f/2.8: 5 elements in 5 groups, 6 aperture blades, 1m minimum focus, 49mm filter thread, 225g.
- Focal length
- 100mm
- Max aperture
- f/2.8
- Mount
- Pentax K
- Format
- 35mm
- Elements / groups
- 5 / 5
Known for
- Portraits
- Candid photography
- Events
- Compact telephoto
Considerations
- f/2.8 limits low light
- 1m minimum focus
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 telephoto
Rendering: Sharp, punchy
Colour: Neutral
Silverlog's editorial rating, 1 to 5; five is best. Not lab-measured.
Common issues
- Focus ring wear
Buying guide
Check focus smoothness.
Specifications
| Mount | Pentax K |
| Focal Length | 100mm |
| Max Aperture | f/2.8 |
| Min Aperture | f/22 |
| Aperture Blades | 6 |
| Min Focus | 1m |
| Filter Size | 49mm |
| Weight | 225g |
Optical design
| Formula | Telephoto |
| Elements | 5 |
| Groups | 5 |
| Coating | SMC (Pentax) |
Pricing
- Typical used price
- £50 - £100
- Mint
- ~£140
Indicative, no dated source.