DxOMark has introduced a new metric of lens sharpness that it’s calling the ‘Perceptual MegaPixel’. This is designed to give a simple, easily-understandable indication of how a lens impacts on the resolution of the camera with which it’s paired. The measurement is based on standard MTF (Modulation Transfer Function) testing, but also takes into account the sensitivity of the human visual system to detail. The data can be explored over at the DxOMark website.