Graph of MTF data from all Photozone.de tests of Canon-mount telephoto lenses.
All lenses tested identically on the same Rebel XT.
NOTE: Klaus has noted that the MTF results from the 70-200/2.8L IS, 100-400L IS, and 50-500EX are lower than what he expected of a "good" copy of those lenses. He hopes to test another sample of each of them sometime. (You can see that the EOSpix.com data yielded notably better results for a different sample of the 70-200/2.8L IS as well as the 100-400L IS.)
Also note that the official PZ 300/4L IS, 70-200/4L and 70-200/2.8EX data shown is from 2nd copies of those lenses, which superceded the original data in the respective PZ reviews since the results from the 1st samples tested were much lower and screamed "substandard." The data for those inferior samples is shown with DOTTED (not dashed) lines. Too bad sample variation can be so huge!