Lens adapter compatibility

Canon EF lenses on Pentax K cameras

Can you use Canon EF lenses on Pentax K cameras? Not with a simple adapter — infinity focus is lost. The Canon EF 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 flange
45.46 mm
Pentax K flange
Verdict: No infinity focus — the Canon EF flange is 1.5 mm shorter than the body's, so an adapter would need corrective glass.

What to expect#

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.

Other systems for Canon EF lenses#

Frequently asked questions#

Will Canon EF lenses autofocus on Pentax K?

This adapter direction is not practical.

Does a Canon EF 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