The Canon EF 70-210mm f3.5-4.5 USM is a much later lens than the Canon EF 70-210 f4 also tested here and although it is a modern two touch lens the focusing ring is small and poorly positioned close to the body, so in terms of handling it could be better. Another common complaint with this lens is that the friction on the zoom ring is fairly low allowing the lens to zoom out anytime you point the camera down, and in, if you point the camera up, unless you hold on to the zoom ring the whole time. Build quality as a whole is good rather than excellent, with a reasonably even but not silky smooth zooming action. The big plus points in this lens’s favor are the silent USM focusing and the faster than average maximum aperture.
As with all telephoto lenses, performance at wider apertures is very important, and at maximum aperture the Canon 70-210 f3.5-4.5 USM produces very sharp results in the center and is quite good in the corners except at 70mm. Unfortunately vignetting at 210mm and full aperture with the Canon EOS 5D is among the worst I’ve seen - it starts to get really obvious from about 120mm and up. It does reduce as you stop down but it’s still very noticeable at f5.6.
On the plus side sharpness in the center field is excellent at 210mm and f5.6 and even the edge performance is very good. It’s a similar story down to about 100mm, when the edges start to soften again, and by 70mm, although the center is still very good, the edges are poor.
In the end, although this isn’t a bad lens, it just doesn’t work well with the Canon EOS 5D, with poor edge sharpness at the short end of the zoom range and extreme vignetting at the long end, there are many better choices out there.