>>2926273>>2926280I have OM-D E-M10 and I've used it with a bunch of adapted lenses. Soviet M42 lenses are pretty okay, but the doubled focal length limits their usefulness. Pic related was taken with a Helios 44M-4. Focusing is bothersome since it takes a while to find the sweet spot, and you can't trust the lens' own scale because it shifts a bit, which also means you need to figure out where the infinity point is since the lens will focus beyond it. Focus peaking at least on my model is a meme that has only limited utility value, it gets completely inaccurate beyond close ranges and in visually busy scenes. Avoid the tempting 28mm Takumar, its edge performance is utterly abysmal on M4/3, also some 135mm's display pretty bad chromabs on it.
So far the best adapted lenses that I've found are Minolta MD glass, 2.8/28, 2/45 and 5.6/300 were all pretty great. Especially the 28mm soundly beats the Takumar as a poor man's standard glass.