Our lens tests are based on a two-stage procedure. First, lab tests are carried out shooting two test charts under controlled lighting conditions. The results are processed using Imatest Master, so that we can quantify optical performance in terms of sharpness, distortion and chromatic aberrations. Overall quality is assessed at the centre, edge and corners of the images. Some of the lenses in this group, however, intentionally blur images towards the edges of images, so low scores aren’t necessarily a bad thing.
For real-world testing, we use each of the lenses under varying indoor and outdoor lighting conditions. Overall handling is checked, along with smoothness and precision of controls. In some cases, the minimum focus distance and the aperture of lenses are not even specified by the manufacturer, so we…