The pixel size of digital sensors cannot be reduced at will without an increasing image noise and decreasing dynamic range. For this reason, larger sensors for professional Digital backs providing for an ultimate resolution (currently up to approx. 60 megapixels) have been developed. The digital lenses, designed for smaller sensor formats, with an image circle around 70 mm, do not allow hardly any camera movement when applying such large sensors. That is why Rodenstock developed the HR Digaron-W lens series with image circles from 90 mm up and an almost diffraction limited high resolution.The shorter focal length of wide-angle lenses causes larger light incident angles at the margin of the image. This results in some blur because of astigmatism, spherical aberration and color fringes produced by the protection glass of a thickness of approx. 2 mm in front of the light-sensitive sensor plane. This can be visible with high resolution sensors. Therefore, the optical effects of this glass plate have been taken into consideration for the calculation of the HR Digaron-W 50 mm f/4 Lens.