M42. To k mount adapter

I am hoping to acquire on of these adapters .
I like to use " catch in focus" when using manual focus lens , and am wondering if an m42 lens would work using this mount. If anyone has any knowledge of this . Regards

I don't see any reason why it should not. I use a lot of manual old glass and the focussing system does just the same as it does with newer glass -- it bleeps with a green hexagon when it thinks the focus is OK. It will do exactly the same in reverse with catch in focus. Instead of you twiddling the lens at something a set distance away, you set the focus and let the subject do the twiddling.
It's worth having one of these adapters anyway so you can use M42s. Check that your camera will stop one of these lenses down however (green button) or get lenses with auto-manual switches

Ye it will work just fine. The simple and well made Pentax Adapter K is the best option, but not the cheapest of course, and will give infinity focus.

M42 lenses work more conveniently than M series K mount ones. These are all non-electronic so the DSLRs cannot stop them down in the usual way, but the M42 will have an A/M switch. Focus on A, with the lens wide open, and then turn the switch to M to stop down to the set aperture, meter and shoot.