Canon EF 70-300mm f/4-5.6 IS USM - £400/$550
Considerably larger and heavier than the Canon EF 75-300mm f/4-5.6 III USM, this design was launched back in 2005. It's not exactly state-of-the-art, and features a dated IS (Image Stabilization) system that only offers a three-stop benefit, unlike the four-stop systems fitted to many current lenses from Canon and other manufacturers. There's also no automatic panning detection, so you have to manually switch between two modes for static or panning shots.
In most respects, build quality feels better than in Canon's cheaper 75-300mm lens, and in addition the 70-300mm has a UD (Ultra-low Dispersion) element intended to boost contrast and resolution while reducing colour fringing.
However, the USM autofocus is still only of the basic motor-based type, and the front element rotates during focusing. Unlike the cheaper lens, this one also suffers from appalling zoom creep.
Sharpness is good throughout the entire zoom range, and is better at the 300mm focal length than with on competing lenses. Despite the UD element, however colour fringing is still quite noticeable at long zoom settings. Autofocus speed is sluggish, especially at the 300mm end of the zoom range, with similar performance to Canon's cheaper 75-300mm.
We'd have expected ring-type USM to be fitted to this lens, considering its price. There's no doubt it's a better lens than the Canon 75-300mm, but there's still plenty of room for improvement.
Sharpness test
Test results are excellent for sharpness at the centre of the frame, but less impressive towards the edges and corners of images.
Fringing test
Not quite as poor as Canon's non-IS 75-300mm lens, but colour fringing is still often noticeable at the 300mm end of the zoom range.
Distortion test
Barrel distortion is the worst in the group at 70mm, and there's noticeable pincushion distortion between 200mm and 300mm.
Image test verdict
The Canon 70-300mm hardly sets the world alight in terms of image quality, but sharpness at the centre of images is very good indeed.
