06-20-2013, 06:27 AM
Quote:Hi there, I just got my new 75mm lens and of course took a whole lot of "test" pics. The sharpness is incredible but only upto f/8. After that the images become unbelievably blurred, actually images taken with 70-300 are much sharper. Is this "normal" and my expectations are too high? Of course to return the lens to B&H shouldn't be a problem if I want to forfeit the shipping costs and quite a high customs duty. I feel I am trapped...
The first example is f/5.6, the 2nd one is f/16:
56.jpg
f/8 = f/16 in conventional terms - do you really need more than that in the real life ?
f/16 is therefore equiv to f/32! On full format cameras images will also be muddy at this setting. This is simply diffraction.