I'd say that setting the aperture ring at just a smidge down is very very easy, just a tiny twist. You can check it with the DOF button, yes even the F100 has it. Just press the button and turn while looking into the lens, and when you see the aperture blades just start to cover the edges then you have it. Just a dab will do ya, like Breelcreem! I've also modified several lenses with 1/3 stop clicks at my favorite/preferred settings.