The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 17-40mm f1.8 and the Canon RF 28-70mm F2L 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 RF 28-70mm F2L USM is the longer of the two lenses at 140mm. The Sigma 17-40mm f1.8 with a length of 116mm, is 24mm shorter. Besides being longer, the Canon RF 28-70mm F2L USM also has a larger diameter of 104mm compared to the Sigma 17-40mm f1.8's 73mm 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. Sigma 17-40mm f1.8 weighs 535g, which means it is 895g (62%) lighter than the Canon RF 28-70mm F2L USM which has a weight of 1430g.
Below you can find the dimension and weight table of the Standard Zoom Lenses in Canon RF Mount for size comparison purposes.
Standard Lenses in Canon RF Mount for Size Comparison
Filter Threads
The Sigma 17-40mm f1.8 has a filter size of 67mm whereas the Canon RF 28-70mm F2L USM has a 95mm 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 Sigma 17-40mm f1.8:
And these are the 95mm filters that we recommend for the Canon RF 28-70mm F2L USM:
Lens Mounts
Both the Sigma 17-40mm f1.8 and the Canon RF 28-70mm F2L USM has the same Canon RF lens mount. Some of the latest released cameras that are compatible with the Canon RF lenses are Canon R50 V, Canon R100 and Canon R50.
Sigma 17-40mm f1.8 is also available in the Sony E , Leica L and Fujifilm X mounts.
Focal Range
Sigma 17-40mm f1.8 has a focal range of 17-40mm and
2.4X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
27.2-64mm when used on a APS-C / DX format camera.
On the other hand, the Canon RF 28-70mm F2L USM has a focal range of 28-70mm and 2.5X 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 - 112mm.
