Adapting APS-frame lens to full-frame camera may generate vignetting, which is not caused by adapters (some cameras could correct it by adjust APSC). On the other side, Adapting full-frame lens to APS-frame camera provides excellent edge-to-edge sharpness. The smaller image field helps minimize the effects of lens distortion and aberration by using the 'sweet spot' or center of the larger lens image circle. And it will magnify the focal length by 1.6 on Canon, 1.5 on Nikon and Sony, 2.0 on M4/3 camera.