I moved up from 35mm to a Pentax 6x7, never regretted it, still have it, love it. I would like autofocus sometimes when photographing portraits of young children, etc. There is an adapter that allows you to use your Pentax 6x7 lenses on a 645N autofocus Pentax, so you can build a system with both cameras and add the autofocus lenses you need, say maybe a 150 2.8 AF for the 645N for portraits and use your other manual focus lenses on either camera, or you can sell one if you decide you like one or the other better and still be able to use your lenses. I am considering a Pentax 645N, but haven't gotten the money up for it yet. If your age and eyesight have anything to do with your interest in autofocus, be aware that a lot of the older models of medium format cameras are very dim and you may need a bright screen from Maxwell or some other source to be able to focus as well as you might like. I had my 6x7 Pentax modified with a Maxwell screen and the difference was amazing, also get a good tripod and solid head/mounting equipment for medium format. Good luck on your vacation.
Doug Webb
