Good timing. My Pentax 6x7 had been setting for about a month and a half. I picked it up yesterday and had the worst time trying to focus. I figured it was the camera, as I can still focus fine with my Canon T3. The difference being, I can adjust the diopter on it. Then I switched to focusing with my left eye. That was somewhat better. But, I would rather use my right eyeball for focusing. Habit, I suppose. I was working with the 90mm 2.8 attached, so I would say the 90mm is somewhat difficult to focus also . . . that is, if you have old eyeballs like mine. I only use 1.75 reading glasses as needed. So, I too am interested in this subject.