This is a technical page. Skip it unless you understand MTF. Or see Making Sharp Images.
Most MTF charts plot contrast (MTF) at a distance from optical center, graphing 10/20/40 line pairs per millimeter, not so here.
These charts graph MTF from zero to 200 line pairs/mm, and there is one graph for each distance from the optical center. A distance of 21.3mm is the corner of a 35mm frame; a distance of 30.4mm is the corner of a 56mm X 24mm frame, which is what you get fully shifted 10mm in the long direction.
Note that Canon and Nikon MTF charts only go to 30 line pairs/mm. Zeiss supplies 10/20/40 line pairs/mm for most of its optics. So the charts on this page should be read out to the “40” mark only, to be (somewhat) comparable to the standard Zeiss MTF graphs.
Article continues for subscribers...
diglloyd Advanced Photography includes hundreds of pages of exclusive coverage and high resolution, Retina-grade example pictures detailing Canon and Nikon DSLR bodies and their lenses, with in-depth analysis of sharpness and contrast, color, bokeh, vignetting, distortion, MTF, and flare. Also included is a wealth of in-context technique and workflow insight. Since 2006, diglloyd Advanced Photography is the authoritative review and on-line reference for discerning Canon and Nikon shooters. Subscriptions cost $ per year.