HOW WE TEST

We combine real-world shooting results with rigorous lab testing to arrive at our overall ratings

To test real-world performance, we use lenses in all sorts of lighting conditions, for indoor and outdoor shooting scenarios. We check for good build quality and handling, smooth and precise operation of all controls, and we test the speed and accuracy of autofocus.

We typically test full-frame compatible EF lenses on a range of full-frame and APS-C format bodies, whereas EF-S lenses that are designed specifically for APS-C format bodies are only tested on cameras like the EOS 90D. EF-M and RF lenses are tested on respective EOS M and EOS R type mirrorless bodies. In-camera corrections for chromatic aberrations and peripheral illumination are disabled throughout all testing, to better reveal the true performance of each lens on test.

We also run a full range of lab tests under controlled conditions, using the Imatest Master and DXO Analyser suites. Photos of test charts are taken across the range of apertures and zoom settings, then analysed for sharpness, distortion and chromatic aberrations (colour fringing).