The human eye and the equipment chain (3/4) Lenses and sensors/film Highest quality fix lenses are under optimal conditions (center / stop down / contrast) able to perform up to 150 lines/mm (75 line pairs/mm). This results in maximum 3600 lines for the height of the FX format. This is equivalent to a 20 MPixel sensor. Zooms have of course a somewhat lower performance. Average lenses perform more in the range of 100 lines/mm what can be handled with an 8 Mpixel sensor. The lens and not the today sensor technology is the limiting factor. Also in analog photography the lens is more or less limiting. The good old Kodachrome 25 film for slides performs with a maximum of 200 lines/mm. This is equivalent to a 7620x5080 pixel sensor (39 Mpixels) which is in line with the Nikon D800 sensor. The conventional color films are in the range around 100 lines/mm. For a properly scanned slide (with 2800 dpi scanner) a FX format picture with 3800x2600 pixels (10 Mpixel) becomes available.