Response to out of focus film

Dear Jorge, somehow I do not get the gist of your question. Do you want to know if I read journals or do you want to know if "I am reading from them"? In the first case yes, in the latter I must admit that "I am hardly reading from them". Let's leave the joking aside. Difraction is a very visible phenomenon. I must admit I have no problem seeing the effects on especially on my slides but also on prints taken with a "sharp" film (perhaps a doctor would have a cure for this). Any grain focuser will show you the difference in a more than obvious way. Take two images, one at f8-11, the other at f22-32. It is advisable to include an edge. Project the negs on the baseboard of your enlarger and focus on them with your grain focuser. The results are more than obvious, but you can see this yourself. The problem doing this test with a Hasselblad is that (also depending on the focal length of your lens) the more you open the iris, the more the flatness problem of the back will affect the result and thus will counteract the higher resolution the lens will provide with a larger f stop. This is especially visible with telephoto lenses. I used Hasselblad type backs for decades and I know what I am writing about. There is a "quick and dirty" test that does not necessitate a collimator (which shows the problem in all its severity): Take the back off and just pull the darkslide with a film loaded. You virtually see the film bulging outward. Some people might say that this minimal bulge would not be critical, BUT even minimal aberration from the focal point will have visible effects. Due to this I changed to a medium format camera and roll film insert for large format with a direct film path and again I must admit that I see the difference. BTW, congratulations on your advanced degree!

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