I just rented and AFD 645 about two weeks ago and was able to use all of my manual focus 645 lenses on it in manual focus mode...the inserts are also the same, there are two models of metered prisim finder for the 645 series of cameras and they are quite often offered on ebay, and several have gone for $150.00 or less in great shape, the current PDS prisim finder I have for mine, I got on my model J with a 150 lens for $212.00 and it works like it was new.

Dave Parker
Ground Glass Specialties