Hello, I have a heinz kilfit 90mm 2.8 macro lens lying around with a 39mm screw mount. I can't seem to find any information about the flange focal distance. I'm 99% sure it is longer than the 28.80mm for m39 though. I just got a Zorki 1, is there a way to calculate what distances I can get in focus when using the lens on a m39 body?