I've just started becoming familiar with using a collimator to check the flange depth on lenes but had a quick question regarding reading the results (IHI).
I am using a gecko-cam auto-collimator; with a lense at infinity and open fully I can measure the flange focal distance however, when I raise the f/t-stops, with some lenses the 'H' begins to move - changing my result. Is this a problem as it only happens with some lenses and should I compensate this into my results? If so how?
I hope that was clear enough; please don't hesitate to ask me more questions!