The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 18-250mm F3.5-6.3 DC OS HSM and the Canon 28-135mm f3.5-5.6 IS USM for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Sigma 18-250mm F3.5-6.3 DC OS HSM is the longer of the two lenses at 101mm. The Canon 28-135mm f3.5-5.6 IS USM with a length of 97mm, is 4mm shorter. Besides being longer, the Sigma 18-250mm F3.5-6.3 DC OS HSM also has a larger diameter of 79mm compared to the Canon 28-135mm f3.5-5.6 IS USM's 78mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Canon 28-135mm f3.5-5.6 IS USM weighs 540g, 14% (88g) lighter than the Sigma 18-250mm F3.5-6.3 DC OS HSM's weight of 628g.
Filter Threads
Both the Sigma 18-250mm F3.5-6.3 DC OS HSM and the Canon 28-135mm f3.5-5.6 IS USM have the same Filter thread size of 72mm.
Below are links to the 72mm filters that we recommend you to consider for these lenses:
Lens Mounts
The Sigma 18-250mm F3.5-6.3 DC OS HSM has the Sony Alpha lens mount whereas the Canon 28-135mm f3.5-5.6 IS USM has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Sony A68, Sony A77 II and Sony A58 for the Sony Alpha Mount and Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount.
Sigma 18-250mm F3.5-6.3 DC OS HSM is also available in the Canon EF , Nikon F (DX), Pentax KAF3, Sony Alpha, Sigma SA, Canon EF, Nikon F (DX), Pentax KAF3 and Sigma SA mounts.
Focal Range
Sigma 18-250mm F3.5-6.3 DC OS HSM has a focal range of 18-250mm and
13.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27-375mm when used on a APS-C / DX format camera.
On the other hand, the 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 a 35mm (FF) equivalent of 44.8 - 216mm.
