Marek Isalski, Entropy Source
Lens Comparison at 300mm
Old refers to the 75-300mm f/4-5.6 II, while new refers to the 70-300mm f/4-5.6 IS USM. Pictures were converted from the 7D’s full resolution RAW to JPEG with identical settings, aligned in Photoshop, then cropped to a 480x480 pixel section at 100% zoom.
The images presented are taken at ISO 1600 in the middle of the field of view, approximately from the area highlighted here:
No image stabilisation was used: the camera was physically steadied and the best of five pictures was chosen for the comparison.
f/5.6 Old
New
An appreciable improvement, both in contrast and clarity.
f/9 Old
New
At f/9 the quality of the new USM lens is marked.
f/20 Old
New
At f/20 the quality converges slightly, but the contrast of the new lens is still much better.
f/45 Old
New
I doubt I would ever shoot at f/45, but the new lens still has much higher contrast.