I keep hearing about "any k-mount lens" fitting the newer DSLR's but I've struck 3 incompatibilities that deal with the best part of my old gear (not much I can salvage from it).
First is an issue with the flange on 2 old Sigma lenses mentioned here:
Old manual Sigma lens "for K mount" won't fit on K100d - Photo.net Pentax Forum that effects 2 old Sigma Lenses I have (the only two) - a 28mm Macro and a 70-210 Zoom. Seems the flange has to be ground back for it them fit my k-r. Not sure it is worth it for the 70-210 (new lens on the way) but am a bit disappointed about the 28mm. Has anyone done the grind/trim?
What I'm worried about is:
"I saw that your flange may have been grind down too much as the flange is meant to protect the shutter blade actuation lever (stop down) from hitting by K lens body upon lens mount"
but then another post says
"Don't worry, I've seen plenty of older, 3rd party lenses that don't have a flange at all, so you shouldn't have any problems."
Not sure if I'll grind the 28 flange yet but if I do should I watch how much I take off or not? Last thing I want is to cause camera damage.
Other issue is with a set of King Auto Extension tubes. These weren't cheap when I bought them but would sell cheap now. They fit the body of the k-r but the kit 18-55 lens won't fit them. That's a shame because they are auto and have a full series of contact pins.
Consolation is that the 28 mm fits the tubes which fit the body bit it's all manual and I don't think I'd be able to focus with that combo (I think the focal plane might be out of reach). They'll work with an old Pentax 50mm F2 but that's about it.