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Message: <blockquote data-quote="Derry" data-source="post: 1730060" data-attributes="member: 55358">Marcel, I shoot with a 70-200 and a 1.7 TC,, using a D300,, I am an (aged) astronomer and have always tested all my lens for critical sharpness,, my 70-200 was almost dead on but with the TC 1.7 behind it the camera needed a +5 for fine focus set up,, for my test I do all comparisons at 200 to 300 increase so you can really see what is sharp or not,, also test the lens at different distances,, even the best lighting condition cannot overcome a lens that is just a tad OOF,, would certainly recommend you assure the lens and body combination are correct before starting other testing,, Derry</blockquote>