I just got one of these meters. Very interesting tool so far. A question. I was measuring the light drop off on the baseboard with the meter, when I start playing with the aperture of the lens. Should each stop of the lens match up with a single stop on the meter? ie: if the meter reads 7.5 at F11, then shouldn't it read 8.5 at F8? I'm find that this is the not the case with my EL-Nikkor 50/2.8. I haven't tried my other enlarger lenses yet. If it should be the case, and it is not then what could be problem? The click stops on the lens are not correct?