Adapter guide

M39 lenses on MFT

Yes, this works. M39 has a 28.8mm flange distance and Micro Four Thirds has 19.25mm, so a 9.55mm mechanical adapter with no glass fills the gap and infinity focus is preserved. Focus and aperture stay manual.

M39 flange: 28.8 mm
MFT flange: 19.25 mm
Adapter thickness: 9.55 mm
Optical elements: None required

Setting it up

Enable Shoot w/o Lens (Panasonic) or leave Release Priority on (Olympus and OM System), then enter the focal length for in-body stabilisation. The 2x crop doubles the apparent focal length, so a 50mm frames like a 100mm.

Manual aperture ring, no diaphragm automation. The ring stops the lens down directly.

M39 lenses and their field of view on MFT

Effective focal length changes with sensor size. The lens itself does not change; the smaller sensor simply captures a narrower part of the image circle.

M39 lenses adapted to MFT, with effective focal length by sensor format
Lens	Focal length	Aperture	Frames like (Four Thirds (2x))	Years	Used value
KMZ Jupiter-8 50mm f/2	50mm	f/2	100mm	1950s-1980s	$30 to $120

Frequently asked

Do M39 lenses work on MFT cameras?

Yes. A plain M39 to MFT adapter works with no optics. M39 has a 28.8mm register and Micro Four Thirds has a 19.25mm register, so the adapter is a 9.55mm tube that puts the lens exactly where a M39 body would. Plain threaded adapter for mirrorless, no rangefinder coupling needed. A helicoid adapter adds close focus below the 1m rangefinder minimum. Do not confuse with the Zenit SLR M39 mount, which uses the same thread at a 45.2mm register.

Do M39 lenses focus to infinity on MFT?

Yes. Because the adapter restores the native 28.8mm register, infinity focus is preserved and the full focus scale on the lens stays accurate. Adapters machined slightly short let the lens focus past infinity by a small margin, which is harmless; adapters machined long stop short of infinity, so buy from a maker with tight tolerances.

What focal length does a M39 lens become on MFT?

On Four Thirds (2x) MFT bodies (Lumix G, GH, GX; OM-D and PEN; OM-1 and OM-5) a 50mm lens frames like a 100mm lens on full frame; the aperture and depth of field at a given distance do not change.