M42 adapter ring that works ok
I appreciate your input, but as I said in the first post, I have the (expensive) original Pentax adapter.
I am interested in getting some cheaper ones that I would be willing to take off the tab and leave it on a lens all the time.
I know it's possible, as I got one that worked just fine in this way (that offer no longer available on eBay).
I then got some others that are awful (grind the camera, go in stiff, go past the point where they are supposed to etc – in short, useless, even dangerous to the camera).
I'd like to get a line on some, not too expensive, that someone has tried and knows work ok.