MTF CURVES. The MTF is shown in each case for the max. aperture as well as for 2.0 and 5.6 for long focus distances (infinity). The contrast is plotted in percentages for 5, 10, 20, 40Lp/mm over the height of the format for tangential (dashed line) and sagittal structures (continuous line) for white light. The plots for 5 and 10Lp/mm offer an impression of the contrast behavior for coarser object structures, while the 20 and 40Lp/mm plots document the resolution capability for fine and finest object structures.DISTORTION. Distortion is the deviation of the actual image height from the ideal image height, whereby the ideal image height is calculated from the object height and the reproduction scale. Relative distortion states the percentage deviation of the actual to the ideal image height. The image height of 21.6mm is the radial distance between one corner of the image field and the middle of the image field (image format 24mmx36mm). The graph of the effective distortion illustrates the actual line and the curvature of horizontal and vertical lines in the image horizon.VIGNETTING. Vignetting is a continuous decrease of image brightness (irradiance) towards the edges of the image (shading compensation, darkening of the image corners). The graph shows the diminishing brightness in percent applied over the image height.100% means no vignetting.