The new Canon 55-250 STM is terrific! First of all, it is from Kuststoff and has no metal bayonet, but that does not bother me, and has also led with my old kit lens to no difficulties. The advantage is that the lens is very light, which is very pleasant for longer shootings. The processing is of course not at L-level, but overall good.
The most important thing for me is the picture quality and I must say I am very excited! So sheep pictures are me previously never managed with the Tamron 70-300 Di SP. Together on the EOS 70D, the autofocus is fast and accurate. Since this is a new lens, must be looked at older cameras previously, whether it can be used there, for example, has for the EOS 650D possibly initially a firmware update can be performed.
Should also be mentioned that you may find a slight but already visible vignetting at the wide angle (at a vignetting are the images in the corners slightly darkened). However, this is not a problem, as this is automatically calculated out of the camera when you create the JPG images, or you can do this yourself very easily, if you develop the RAW images with eg Lightroom itself. May need to be updated with the EOS Utility program, the objective data of the camera, this is also very easy. This is only an indication, if someone trips over it and do not know they can make do.
In the customer images, for example, see pictures from one of our guinea pigs. Razor sharp, even at 100% view and no extra sharpening with Lightroom or the like.
From me a strong buy recommendation for the great lens!
