prime35mmvintage
SMC Pentax-M 40mm f/2.8 Pancake
Pentax · 1976-1984
Pentax's legendary pancake lens. Incredibly compact at just 18mm depth. The 40mm focal length is slightly wider than 50mm, offering a unique perspective. Perfect for discrete street photography.
Known for
- Street photography
- Travel
- Discrete shooting
- Everyday carry
Considerations
- f/2.8 limits low light
- Longer minimum focus distance
Optical Characteristics
Sharpness (wide)4/5
Sharpness (stopped)5/5
Contrast5/5
Flare Resistance5/5
CA Control4/5
Vignetting Control4/5
Distortion Control5/5
Bokeh: Smooth for size
Rendering: Clean, modern
Color: Neutral
Common Issues
- Focus ring wear
- Small focus throw
Buying Guide
Iconic lens commanding premium prices. Check focus smoothness. A unique piece of Pentax history.
Specifications
MountPentax K
Focal Length40mm
Max Aperturef/2.8
Min Aperturef/22
Aperture Blades6
Min Focus0.6m
Filter Size49mm
Weight110g
Optical Design
FormulaTessar
Elements5
Groups4
CoatingSMC (Pentax)
Pricing
£100 - £200
Typical used price
Mint: ~£280
Collectible pancake premium
Adapts To
Sony EFujifilm XCanon RFMicro Four Thirds
Compatible Cameras
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Last verified: Jan 2026Report an error