Just got a F-mount-adapted Helios 44M, focussing to infinity thanks to a printed plastic part. A very good job; the lens came 100% clean and dust-free, although the barrel shows signs of usage and focussing action is on the stiff side.
The lens is astounding or, at any rate, better than its so-so reputation. Center sharpness is excellent (even at full aperture), but the field may not be that flat. There is vanishingly little LoCA (!!!) which is quite valuable to my eyes. Unfortunately, I got no time for reports now, too busy, but expect some shots under the "December 2020" thread.