Good points, Alan, and I was referring to lenses for 35mm negatives.(posted 9547 days ago)I recently purchased an enlarger with a top level 100mm f4.5 lens. I havn't printed with it yet, but in playing around with a 2 1/4 negative and a high quality grain focuser, it appears that f11 is the best aperture for resolution across the field. Until I print, I can't make a judgement about vignetting.