I recently beefed up my Pentax 67 lens collection so now I have 3 of the newer variety and 3 of the older all metal type. The newer ones (55,135,165) all focus very easily with little effort. Of the older ones (75,90,105) the 75 and 90 take more effort to focus than the 105 which is as easy as the newer ones. The 75 and 90 seem stiffer to turn but very smooth with no sense of grit or anything.
I am wondering why the 105 which is just as old as the other two is so much easier to focus. It is buttery smooth and very easy to turn. I am wondering if the other lenses actually need a CLA, or do I just need to sit in front of a movie on TV and work them till they get easier. Or if I just work them will they actually get stiffer rather than easier.
There isn't a Pentax repair person in the area I would trust to give me any answer except "you definitely need to bring it in for a CLA".