Jan Brittenson
Senior Subscriber Member
I used to have the 400/4 ED-IF for my P67, and it's a good lens. But not really long enough on 6x7; it should be great with an extender on the new 645D although I found it wanted to be stopped down a notch with the 2x. The 67 image circle makes it a big lens though, quite larger than the Mamiya 500/5.6. The latter is about the size and weight of the Canon 500/4 IS so is somewhat compact for 645. (Doesn't Pentax have a 645 tele lineup?)