I'm just beginning to get into 8 x 10 work, and I've recently picked up a Turner Reich lens for next to nothing to start to try things with. It's a Turner Reich Triple Convertible Series II NO. 5 (12" / 21" / 28"). I've never worked with triple convertable lenses before, so this is my first. The front and rear lens cells both have the same serial number on them - 117424, so I assume that the lens is as it was manufactured at the factory (and not two mis-matched cells). When focusing at infinity, the combination cells look to be 12", the rear cell looks to be 21", however, the front cell focuses at only about 22" instead of 28". So using either the front or rear cell really isn't much different in terms of focal length. The "infinity" I focused at was quite a long distance away - 400 yards. Is it common for these type of lenses to be that far off on the focal distance? Could this have just been a quality control issue at the factory.
I wasn't necessarily planning on using the front cell only, because from what I've read, it's not supposed to be as sharp . However, I am curious that it seems to be so far off.