Well, Carsten, when I try out a new lens I try to ask it how it will do when I shoot it as I usually do. That means at the apertures I normally use. I have a couple of semi-standard targets with some fairly fine detail, for-sure out-of-focus areas, and a good mix of light and dark. So I"ll typically shoot a new lens at f/11, f/16, f/22 at the fence at the end of my back yard. Distance ~ 40', 12 m. Also if a long lens at the stop sign at the end of my block. Distance ~ 1,000', 300 m. And then I look at the transparency or negative at 12x. I've done this more than once, so have reference images to compare with.