I let the lenses EF 75-300 III and EF-S 55-250 IS II directly compete against each other to decide between them. I have a few hundred test images with moderate light (cloudy sky, late afternoon, October) and made some interior rooms with light. These were by far no laboratory conditions and I have tested even for each image all focal lengths and apertures of both lenses, but every now and trying different settings. The pictures were taken almost all of his free hand and some with tripod.
To put it briefly: The EF-S 55-250 IS II has won. The EF 75-300 III goes back.
Why?
1. I am not a big fan of chromatic aberrations. They are ugly and give a sense of lousy camera. These occur at 75-300 on massively. (At least for my model that was so bad that it might even become defective) While the PC are correctable, but I do not want to edit each image on your PC. When 55-250 they are also visible in the 100% view, but not so disturbing.
2. speed of the autofocus is faster at 55-250.
3. Stabilization (IS): I knew before buying. But if you compare it directly, you want to the IS - just in Tele - not to miss. In light conditions, we almost only find here in the far north, I did not like the 70-300.
4. Overall, convinced me the pictures - without exception - from 55-250 more. I had especially more sharpness in the image and overall clearer images. The images of 55-250 look very similar to the kit lens 18-55. If you can live with its quality, the would 55-250 also determined commitments.
5. The zoom range is a matter of taste. The difference in my opinion between 250mm and 300mm rather is marginal.
6. The feel is better at 70-300. The 55-250 is the kit lens 18-55 very similar in appearance.
The camera is an EOS 650D. (Automatic corrections off)
To my review:
I give four stars because the lens is relatively low and a functioning IS brings. Other requests go only for more money in fulfillment. Overall, this corresponds to 55-250 largely what I expected.