Well, let me answer my own question, just for the record. Went to a camera show the other day and had a chance to look through a Leicaflex Standard. It had a short telephoto mounted, I believe. The image was very bright, and it's true that the portions of the image that fell outside the focusing spot (microprism) did not seem to go in and out of focus as I racked focus. BUT -- the focusing spot was very definite in its response. That is to say, I was never in doubt as to whether I was properly focused or not, as I can sometimes find the case with other microprism focusing spots. I can't say to what degree this impression may have been reinforced by the shallower DOF in a short telephoto. I came away with a very positive impression of the camera -- now if only Leica SLR lenses didn't cost so much.