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 lenses on a range of FX and DX bodies, whereas APS-C format lenses are just tested on DX cameras. These include DSLRs such as the D850 and D7500, and mirrorless cameras like the Z 7II and Z fc.
In-camera and Raw processing corrections for chromatic aberration, distortion and vignetting are disabled where possible, throughout lab-testing, to better reveal the true optical performance of each lens. In our lab, we test lenses under controlled conditions, shooting specialist test charts and processing the results with the Imatest Master and DxO Analyzer suites. Test shots are taken across the range of apertures and zoom settings (where applicable), then analysed for sharpness, chromatic aberrations (colour fringing) and distortion. We judge the overall performance by taking both real-world testing and lab tests into account.