There are two types of lenses for which the test results are less relevant: First of all, the Fisheye lenses, which have so much Fisheye distortion that any reliable measurement of sharpness becomes very difficult. Secondly, the macro lenses, whose image quality over the entire field of view is so good in all cases that you can’t go wrong. Of course, there are still quality differences, but the number of megapixels of the camera is often the limiting factor. Image curvature, distortion and/or blurry corners don’t happen with a macro lens.
Sigma 70mm f/2.8 Macro Art: Absolute top on full frame, for a great price!
WITH OR WITHOUT LENS CORRECTIONS?
Lens manufacturers design lenses in which distortion, color separation and vignetting are not optimally corrected. They assume that lens errors will be automatically corrected in the camera (for jpg files) or afterwards in Lightroom or Photoshop (for RAW files). The advantage of this choice, for manufacturer and consumer, is that you can achieve high image quality at relatively low costs, because you do not have to use expensive types of glass to prevent all lens errors. But there are also, usually the more expensive, lenses where a manufacturer has gone to extremes to prevent lens errors in the lens design. CameraStuffReview shows tables and graphs of Imatest results with lens corrections (“in-camera jpg”) and without lens corrections (“RAW” outside of Photoshop or Lightroom). You can thus use the scores that are closest to your workflow.
Don’t forget with macro lenses that they are almost always tested like a normal lens: not at an extremely short distance that the macro lens is designed for. This has to do with the limited supply of test cards with extremely high resolution, so that even at very short distances, the resolution of the test card is still sufficient for a reliable result. We were once commissioned by a Dutch photo magazine to test a number of macro lenses in the macro range with a special set-up. The test results matched the test results with the normal test card or were sometimes even better.
Most likely, the price, dimensions and weight or the scope of application of a macro lens (long focal point for living insects or a short focal point for reproduction work) will be more important to you than the final scores. On the other hand, it’s not crazy to opt for a lens that scores high without lens correction for distortion or vignetting.