Canon EF 24-105mm f/4L IS USM - £920
Like the other full-frame lenses in the group, this one lacks wide-angle potential on an APS-C camera but redeems itself with the longest telephoto reach, equivalent to 168mm.
Unlike the even-pricier Canon EF 24-70mm, this lens has image stabilisation offering a 3-stop benefit in beating camera-shake. The maximum aperture is one f/stop smaller but stays constant throughout the zoom range, enabling tight depth of field at longer focal lengths.
Despite its longer reach, the lens is smaller and rather lighter than the EF 24-70mm, yet maintains the same professional build quality, complete with weather seals. Distortion and vignetting at the wide-angle end are more pronounced than on the EF 24-70mm but are only really noticeable on a full-frame camera.
Sharpness is excellent throughout the entire zoom range, and colour fringing is minimal. Autofocus is extremely fast, practically silent and extremely accurate.
As a full-frame lens for use on either an APS-C or full-frame body, the EF 24-105mm has a lot going for it. It's actually the kit lens for the mighty 5D Mark II and, unlike Canon's other kit lenses, feels a perfect match for a pro camera.