Production
1978 – 1984
Country
Japan
Optical
5 elements in 4 groups
Updated
Jul 20, 2026
Pentax SMC Pentax-M 40mm f/2.8 Pancake
Pentax K · 40mm · f/2.8
Compiled from 2 real reviews · AI-assisted · accuracy-checked · Updated 20 Jul 2026
Overview
The SMC Pentax-M 40mm f/2.8 Pancake is impossibly thin — one of the thinnest SLR lenses ever made. Designed for the compact Pentax ME/MX cameras, it turns any camera into a near-rangefinder experience. Sharp, tiny, and with a unique 40mm perspective.
Verdict: The ultimate compact lens. If you want a tiny, sharp lens for everyday carry, the 40mm pancake is magical.
Optical Character
Bokeh
nice
Color
good
Sharpness wide open
Sharp even wide open
Flare resistance
Some chromatic aberration, especially at wider apertures
Contrast
High
Community Insights
What people love
- Incredibly compact
- Sharp for its size
- 40mm is great focal length
- Makes camera pocketable
- Unique character
What people dislike
- Only f/2.8
- Pentax K mount (not M42)
- Focus ring is tiny
Compatible Adapters
Real adapters from our shop that fit this lens mount.
Standard · ฿325 · In stock
Standard · ฿325 · In stock
Standard · ฿325 · In stock
Standard · ฿325 · In stock
Standard · ฿540 · In stock
Standard · ฿540 · In stock
Standard · ฿540 · In stock
Standard · ฿540 · In stock
Standard · ฿1,250 · In stock
Standard · ฿890 · Out of stock
Pentax K Lenses to Canon EOS R Mount Camera Adapter
Standard · Out of stock
Pentax K Lenses to Canon EOS Camera Mount Adapter
Standard · Out of stock
Sample Photos
Sources (2)
Vintagelensesforvideo
Curated heritage archive
The ultimate compact lens. If you want a tiny, sharp lens for everyday carry, the 40mm pancake is magical.