THE CROP factor of smaller APS-C sensors means that they provide more ‘reach’ than full-frame sensors, which can be a benefit when shooting with telephoto lenses. It is the same as attaching a 1.6x extender to the lens, but without the extra cost, loss of light and reduced image quality. Mount a 500mm lens on an EOS R10 (with an APS-C sensor) and you get the same view as an 800mm lens on a full-frame camera.