The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 18-135mm F3.5-5.6 IS and the Sigma 18-35mm F1.8 DC HSM 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 18-35mm F1.8 DC HSM is the longer of the two lenses at 121mm. The Canon 18-135mm F3.5-5.6 IS with a length of 96mm, is 25mm shorter. Besides being longer, the Sigma 18-35mm F1.8 DC HSM also has a larger diameter of 78mm compared to the Canon 18-135mm F3.5-5.6 IS's 77mm diameter.
Below you can find a scaled side-by-side image of Canon 18-135mm F3.5-5.6 IS and Sigma 18-35mm F1.8 DC HSM to get a better idea of how their sizes compare in real life.
Comparison image of the Canon 18-135mm F3.5-5.6 IS and the Sigma 18-35mm F1.8 DC HSM Size and Weight 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 18-135mm F3.5-5.6 IS weighs 515g, which means it is 295g (36%) lighter than the Sigma 18-35mm F1.8 DC HSM which has a weight of 810g.
Filter Threads
The Canon 18-135mm F3.5-5.6 IS has a filter size of 67mm whereas the Sigma 18-35mm F1.8 DC HSM has a 72mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Canon 18-135mm F3.5-5.6 IS:
And these are the 72mm filters that we recommend for the Sigma 18-35mm F1.8 DC HSM:
Lens Mounts
The Canon 18-135mm F3.5-5.6 IS has the Canon EF-S lens mount whereas the Sigma 18-35mm F1.8 DC HSM has the Canon EF lens mount . Some of the latest released cameras that are compatible with these mounts are Canon T8i , Canon 90D and Canon SL3 for the Canon EF-S Mount and Canon T8i , Canon 90D and Canon SL3 for the Canon EF Mount.
Pentax KAF , Sony Alpha , Sigma SA and Nikon F (DX) mounts.
Focal Range
Canon 18-135mm F3.5-5.6 IS has a focal range of 18-135mm and
7.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
28.8-216mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 18-35mm F1.8 DC HSM has a focal range of 18-35mm and 1.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 28.8-56mm when used on a APS-C / DX format camera.
