We might have a new engineering based on the smooth aperture clicks I guess. Never thought of this. Would be nice! My only russian lens is a badly scratched Industar 50
I have the superb Volna-9 50 mm macro with the progressive aperture, that would be nice indeed. I suck at MF, so never bothered to venture more in to other Russian M42's, but you've got a good point.
you can modify a takumar to do that, all you have to do is remove the ball bearing from under the aperture ring and presto, you have a continuous aperture prime lens.