The Perils of Lens ReviewingReviewing lenses is a perilous task. Unless one is using a full optical evaluation system and has the expertise to interpret the results, evaluations of the technical aspects of lens performance are anecdotal at best, and subject to the vagaries of the changing conditions of real world shooting.

I was a beta tester for, and for a while usedDxO Analyzer, the system that has since been adopted byChasseur DimageandPopular Photographymagazines. I stopped using it in my camera and lens reviews when I realized that the numbers and graphs generated only told me part of the story, and often not the part that I was most interested in.

So, what you get instead is my usual subjective, some would say biased, field evaluation. My testing is done by simply using lenses in the field, in this instance including with the 15mm Distagon inMarrakech, Morocco for a week in January, 2007. My evaluations were subsequently done through close evaluation of the image files on...