Best zoom lens upgrade for canon dslrs: 10 tested

Canon EF 24-70mm f/2.8L USM - £990

A mammoth among standard zoom lenses, this full-frame model is the biggest and heaviest in the group, weighing in at nearly a kilogram. That's five times the weight of the baby EF-S 18-55mm kit lens and, on a camera like the Canon EOS 600D, it feels more like a telephoto zoom.

Uniquely in this group, the lens is at its most self-contained at the longest zoom setting of 70mm, and physically stretches in length as you zoom towards 24mm.

As with the other L-series lens in the group, build quality is extremely robust and luxuries include environmental seals to guard against dust and moisture. The rubber O-ring on the mounting plate is a confidence booster when shooting in the rain, as it greatly reduces the risk of water entering the camera.

Image quality is very good on both APS-C and full-frame cameras, but it's not perfect. Distortions and colour fringing are well restrained, and vignetting is basically a non-issue on APS-C cameras.

However, sharpness proved only average in our tests, which was disappointing given the lens's huge asking price. In practical terms for everyday shooting, the lack of image stabilisation is also a letdown.