The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 28-135mm f3.5-5.6 IS USM and the Canon 24-70mm f4L IS USM for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Canon 28-135mm f3.5-5.6 IS USM is the longer of the two lenses at 97mm. The Canon 24-70mm f4L IS USM with a length of 93mm is 4mm shorter. On the other hand, the Canon 24-70mm f4L IS USM has a larger diameter of 83mm compared to Canon 28-135mm f3.5-5.6 IS USM's 78mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Canon 28-135mm f3.5-5.6 IS USM weighs 540g, which means it is 60g (9%) lighter than the Canon 24-70mm f4L IS USM which has a weight of 600g.
Below you can find the dimension and weight table of the 'Standard Zoom Lenses in Canon EF Mount for size comparison purposes.
Standard Zoom Lenses in Canon EF Mount for Size Comparison
Lens Mounts
Both Canon 28-135mm f3.5-5.6 IS USM and Canon 24-70mm f4L IS USM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Focal Range
Canon 28-135mm f3.5-5.6 IS USM has a focal range of 28-135mm and 4.8X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 44.8 - 216mm.
Canon 24-70mm f4L IS USM has a focal range of 24-70mm and 2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 38.4 - 112mm.