Lens adapter compatibility

Canon EF-S lenses on Pentax K cameras

Can you use Canon EF-S lenses on Pentax K cameras? Not with a simple adapter — infinity focus is lost. The Canon EF-S flange distance is 44.00 mm and Pentax K is 45.46 mm, a difference of -1.46 mm.

-1.46 mm

Space for the adapter

44.00 mm

Canon EF-S flange

45.46 mm

Pentax K flange

Verdict: No infinity focus — the Canon EF-S flange is 1.5 mm shorter than the body's, so an adapter would need corrective glass.

What to expect#

Image circle: Canon EF-S lenses are designed for a smaller sensor (≈1.6× crop), so expect heavy vignetting on a full-frame Pentax K body unless you use its crop mode.

Adapters with an optical element exist for some combinations, but they reduce image quality. A glass-free adapter in this direction only works for macro/close focus.

Canon EF-S lenses you could adapt#

Pentax K cameras#

Other systems for Canon EF-S lenses#

Sony E-mount Canon RF Nikon Z Fujifilm X-mount Micro Four Thirds L-Mount Canon EF-M Fujifilm G-mount Hasselblad XCD Nikon 1 (CX)

Frequently asked questions#

Will Canon EF-S lenses autofocus on Pentax K?

This adapter direction is not practical.

Does a Canon EF-S to Pentax K adapter affect image quality?

Any adapter that restores infinity focus here needs a corrective lens, which typically lowers sharpness and adds a slight teleconverter effect.

Last updated October 03, 2026 · How we calculate · Sources