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 50mm F1.8 STM 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 17-40mm f1.8 is the longer of the two lenses at 116mm. The Canon RF 50mm F1.8 STM with a length of 41mm, is 75mm shorter. Besides being longer, the Sigma 17-40mm f1.8 also has a larger diameter of 73mm compared to the Canon RF 50mm F1.8 STM's 69mm 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 RF 50mm F1.8 STM weighs 160g, 70% (375g) lighter than the Sigma 17-40mm f1.8's weight of 535g.
Filter Threads
The Sigma 17-40mm f1.8 has a filter size of 67mm whereas the Canon RF 50mm F1.8 STM has a 43mm 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 43mm filters that we recommend for the Canon RF 50mm F1.8 STM:
Lens Mounts
Both the Sigma 17-40mm f1.8 and the Canon RF 50mm F1.8 STM 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 50mm F1.8 STM is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 80mm.
