Lens adapter compatibility

Pentax K lenses on Canon EF cameras

Can you use Pentax K lenses on Canon EF cameras? Yes, with a simple mechanical adapter (manual focus). The Pentax K flange distance is 45.46 mm and Canon EF is 44.00 mm, a difference of +1.46 mm.

+1.46 mm
Space for the adapter
45.46 mm
Pentax K flange
44.00 mm
Canon EF flange
Verdict: Yes — a simple 1.5 mm adapter keeps infinity focus.

What to expect#

Aperture control: lenses with a manual aperture ring work directly; electronically controlled lenses (no ring) need a smart adapter or one with a built-in aperture lever.

Focus: use focus peaking and magnification in the viewfinder. Exposure metering works normally because the camera meters through the lens at working aperture.

Other systems for Pentax K lenses#

Frequently asked questions#

Will Pentax K lenses autofocus on Canon EF?

No — adapted lenses are manual focus on this combination.

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

A glass-free adapter is just a precisely machined spacer, so image quality is unchanged when it is built to the right thickness. Cheap adapters can be slightly too thin or thick, which shifts the infinity mark.

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