Yesterday I posted the results of testing two lenses, the Sony 90 mm f/2.8 OSS G FE, and the Sony 70-200 f/4 OSS G FE, on the Sony a7RII. The tests were aimed at detecting and quantifying decentering, using visual appraisal, and showed both lenses to have minimal decentering. Today I’m going to show you… [Read More]

Yesterday I posted this piece on testing for lens decentering using manual focusing. Today I’ll explore an autofocus variant that might be useful when there’s not enough depth of field for the first technique to work well. I mounted a Sony 90mm f/2.8 macro lens on an a7RII and set it up about 20 feet… [Read More]

Yesterday I posted the results of a fairly simple decentering test that requires only an ISO 12233 target, some lighting, a tripod, and a few minutes. Today I’ll show you what happens when you use a slanted edge sharpness analyzer — in this case, Imatest — on the images you saw yesterday. Here’s a crop… [Read More]

[Edit. Although I’m leaving this post up because several people have linked to it, I now recommend a different method as quicker, easier, and less prone to false positives: Simple decentering test And now back to the original post:] You hear complaints all the time about the quality control of various lens manufacturers, and horror… [Read More]