Pentax 645 Focus Problem
A few years back, I had an opportunity to pick up a Pentax 645 that looked to be in good condition. It was very clean with no dings or visible signs of wear. My first roll of film through it indicated my focus was off so I had a local repair shop work on it, and I thought it was fixed, but I never confirmed it. I have a Mamiya system that I normally use, so the Pentax hasn't been out much since I've owned it.
I recently confirmed that the focus problem has not been fixed, so last weekend I set up some white dry erase boards and noted various distances and f-stop settings as I changed distance with the camera. I used a measuring tape to check the distance from the film plane to the focus point. The camera was mounted on a tripod and I focused very carefully. My test confirmed that the camera is focusing well beyond what the split imaging focus indicates in the viewfinder. Focusing at 20 feet appears to actually be infinity, and at 50 feet, nothing is really in focus, as it is focused beyond infinity.
What seems odd to me is that when I focus at a distance that is indicated on the lens distance scale (7 feet or 15 feet for example), that is right where the split image focus says it is in the viewfinder. In other words, the viewfinder agrees with the lens distance scale, but it is actually focused beyond that point. It's almost like the film plane is in the wrong place.