@ozzelot make sure they are the same lens-mount and never buy a converter. m42 to A-mount opened up yet more wallet :'(

@evilstevie too late

here's a pentacon 50mm f/1.8, a helios...

technically, i did not *buy* the adapter. i printed it. but i do intend to buy one for build quality alone, perchance with a focus confirmation chip as well.

@ozzelot get a metal adapter. nothing like the fun of pulling bits of stressed plastic from the shutter mechanisms :(
yes, the nice "normal" (~50mm focal length) primes are good, but find a cheap used "nifty 50" Canon EF 50/f1.8 for less weight and better optical quality

@evilstevie it shall be found.