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 Canon 17-85mm f4-5.6 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. Canon 18-135mm F3.5-5.6 IS is the longer of the two lenses at 96mm. The Canon 17-85mm f4-5.6 IS USM with a length of 92mm, is 4mm shorter. On the other hand, the Canon 17-85mm f4-5.6 IS USM has a larger diameter of 79mm compared to the Canon 18-135mm F3.5-5.6 IS's 77mm 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 17-85mm f4-5.6 IS USM weighs 475g, 7% (40g) lighter than the Canon 18-135mm F3.5-5.6 IS's weight of 515g.
Below you can find the dimension and weight table of the Standard Zoom Lenses in Canon EF-S Mount for size comparison purposes.
Standard Lenses in Canon EF-S Mount for Size Comparison
Filter Threads
Both the Canon 18-135mm F3.5-5.6 IS and the Canon 17-85mm f4-5.6 IS USM have the same Filter thread size of 67mm.
Below are links to the 67mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Canon 18-135mm F3.5-5.6 IS and the Canon 17-85mm f4-5.6 IS USM has the same Canon EF-S lens mount. Some of the latest released cameras that are compatible with the Canon EF-S lenses are Canon T8i, Canon 90D and Canon SL3.
Canon 18-135mm F3.5-5.6 IS is also available in the Canon EF-S mount.
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 Canon 17-85mm f4-5.6 IS USM has a focal range of 17-85mm and 5.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27.2-136mm when used on a APS-C / DX format camera.
