As hinted in the introduction the lens features an UD (ultra-low dispersion) element which is quite unusual for a consumer grade Canon lens. This special kind of glass is usually only used in Canon L (professional grade) lenses.

In the lab the effect of the new design became pretty obvious with surprisingly high resolution figures throughout the range. In fact the data was so impressive that I was already wondering whether I had mixed up the RAW files with a (supposedly) better lens.

The lens produced very good to excellent MTF figures. As to be expected the performance is best at 70mm with excellent center and border quality at all tested apertures. At 200mm and a little more so at 300mm there's a slight decrease in resolution but the results stay easily within very good territory reaching even excellent center figures at the respective performance peaks. Compared to true L grade lenses the contrast level seems to be a tad lower at 300mm. Nonetheless this is truly baffling for such an affordable lens.