Lens · prime
SMC Pentax-M 40mm f/2.8 Pancake
Pentax · 1976-1984
Vintage35mm
SMC Pentax-M 40mm f/2.8 Pancake: 5 elements in 4 groups, 5 aperture blades, 0.6m minimum focus, 49mm filter thread, 110g.
- Focal length
- 40mm
- Max aperture
- f/2.8
- Mount
- Pentax K
- Format
- 35mm
- Elements / groups
- 5 / 4
Known for
- Street photography
- Travel
- Discrete shooting
- Everyday carry
Considerations
- f/2.8 limits low light
- Longer minimum focus distance
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 for size
Rendering: Clean, modern
Colour: Neutral
Silverlog's editorial rating, 1 to 5; five is best. Not lab-measured.
Common issues
- Focus ring wear
- Small focus throw
Buying guide
Check focus smoothness.
Specifications
| Mount | Pentax K |
| Focal Length | 40mm |
| Max Aperture | f/2.8 |
| Min Aperture | f/22 |
| Aperture Blades | 5 |
| Min Focus | 0.6m |
| Filter Size | 49mm |
| Weight | 110g |
Optical design
| Formula | Tessar |
| Elements | 5 |
| Groups | 4 |
| Coating | SMC (Pentax) |
Pricing
- Typical used price
- £100 - £200
- Mint
- ~£280
Indicative, no dated source.