Brian E. Wright
Earlier this year I purchased the international version of the Canon 55-250 STM to use with my Canon SL1 as a lightweight fun setup. I was so impressed with the performance of this lens that I decided to buy the more expensive (3X) Canon 70-300 USM II, not just for the extra 50mm reach, but as a telephoto I could also mount on my Canon 5D3. I also had the expectation that the optics would be better, or at least as good as the 55-250. The build quality and functioning of the new lens were excellent. To make a practical assessment of its optics I tested both lenses on a tripod, using the SL1, same settings, remote release, stabilization off, at 250mm. Same shots at F5.6 and F16. At both of these apertures I found the 55-250 noticeably sharper in the center and on the edge compared with the new 70-300. To find that Canon’s newer, more expensive, more robust lens was optically inferior to the 55-250 was a surprise and a big disappointment. I immediately returned the lens to Amazon with no problem.