The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 17-50mm f2.8 XR II VC LD and the Canon 17-40mm f4.0L 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 17-40mm f4.0L USM is the longer of the two lenses at 97mm. The Tamron 17-50mm f2.8 XR II VC LD with a length of 95mm, is 2mm shorter. Besides being longer, the Canon 17-40mm f4.0L USM also has a larger diameter of 84mm compared to the Tamron 17-50mm f2.8 XR II VC LD's 80mm 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 17-40mm f4.0L USM weighs 500g, 12% (70g) lighter than the Tamron 17-50mm f2.8 XR II VC LD's weight of 570g.
Filter Threads
The Tamron 17-50mm f2.8 XR II VC LD has a filter size of 72mm whereas the Canon 17-40mm f4.0L USM has a 77mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 72mm filters that we recommend you to consider for the Tamron 17-50mm f2.8 XR II VC LD:
And these are the 77mm filters that we recommend for the Canon 17-40mm f4.0L USM:
Lens Mounts
Both the Tamron 17-50mm f2.8 XR II VC LD and the Canon 17-40mm f4.0L USM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon T8i, Canon 90D and Canon SL3.
Tamron 17-50mm f2.8 XR II VC LD is also available in Nikon F (DX) mount.
Focal Range
Tamron 17-50mm f2.8 XR II VC LD has a focal range of 17-50mm and
2.9X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27.2-80mm when used on a APS-C / DX format camera.
On the other hand, the Canon 17-40mm f4.0L USM has a focal range of 17-40mm and 2.4X zoom ratio . When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 27.2 - 64mm.