Hopefully one of you jolly fine fellows can answer a question that has been bugging me for a while!?
When using The Digital Pictures' sample crops to compare lens performance against other lenses or the same lens used on a crop and full frame body, for example, it astounds me how soft the crop body rendition is in comparison. The below link illustrates my question: http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=687&Camera=453&Sample=0&FLI=3&API=3&LensComp=687&CameraComp=736&SampleComp=0&FLIComp=3&APIComp=3
The 70-200 2.8L
IS II is obviously one of Canon's legendary lenses, but why does the crop crop (crop body crop!)- which is a 60D in this case- look so much softer than the full frame 1Ds III? Is it just that the 60D has a very soft output? I chose f5.6 as the aperture for both bodies so there should be no diffraction issues but the comparison is much the same at other apertures anyway. Even more surprising in the above comparison is how soft the corners are on the 60D crops compared to the 1Ds III, which surprises me because the crop body is not using the lens's full image circle. The first time I used TDP's comparison was with ultrawide zooms so I just figured that it was the fact that the full frame ultra wides were performing better than a crop equivalent (think EF-S 10-22 on crop compared against 17-40L
on full frame, but when I started looking at other lenses I saw it was pretty much always the same- the FF crops were visibly sharper with the same lens. Any thoughts?