I have the 150mm. It's a beautiful lens, very flexible and forgiving and, to be honest, it doesn't bother me to shoot it wide open. DOF is short, of course, so a tripod and not being in a hurry is best. If you want to hand hold it, sure, stop it down a couple of notches. With the 45mm (and certainly with your 30mm) it's as sharp as you'd want it at any stop. Increasingly I find myself being less concerned with sharpness and more with subject matter and composition.