The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 15mm f1.4 DC C and the Canon RF 35mm F1.8 IS STM Macro for their suitability to various photography scenarios:
Size and Weight Comparison
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 15mm f1.4 DC C weighs 240g, which means it is 65g (21%) lighter than the Canon RF 35mm F1.8 IS STM Macro which has a weight of 305g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Canon RF Mount for size comparison purposes.
Wideangle Lenses in Canon RF Mount for Size Comparison
Filter Threads
The Sigma 15mm f1.4 DC C has a filter size of 58mm whereas the Canon RF 35mm F1.8 IS STM Macro has a 52mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 58mm filters that we recommend you to consider for the Sigma 15mm f1.4 DC C:
And these are the 52mm filters that we recommend for the Canon RF 35mm F1.8 IS STM Macro:
Lens Mounts
Both the Sigma 15mm f1.4 DC C and the Canon RF 35mm F1.8 IS STM Macro 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 15mm f1.4 DC C is also available in the Fujifilm X and Sony E mounts.
Focal Range
Sigma 15mm f1.4 DC C is a prime lens with fixed focal lenght of 15mm which has an effective (full-frame 35mm equivalent) focal range of
24mm when used on a APS-C / DX format camera.
On the other hand, the Canon RF 35mm F1.8 IS STM Macro is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 56mm.