The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 56mm F1.4 C 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 56mm F1.4 C is the longer of the two lenses at 60mm. The Canon RF 50mm F1.8 STM with a length of 41mm, is 19mm shorter. On the other hand, the Canon RF 50mm F1.8 STM has a larger diameter of 69mm compared to the Sigma 56mm F1.4 C's 67mm 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, 42% (120g) lighter than the Sigma 56mm F1.4 C's weight of 280g.
Filter Threads
The Sigma 56mm F1.4 C has a filter size of 55mm 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 55mm filters that we recommend you to consider for the Sigma 56mm F1.4 C:
And these are the 43mm filters that we recommend for the Canon RF 50mm F1.8 STM:
Lens Mounts
The Sigma 56mm F1.4 C has the Fujifilm X lens mount whereas the Canon RF 50mm F1.8 STM has the Canon RF lens mount. Some of the latest released cameras that are compatible with these mounts are Fujifilm X-T30 III, Fujifilm X-E5 and Fujifilm X-M5 for the Fujifilm X Mount and Canon R6 V, Canon R6 III and Canon C50 for the Canon RF Mount.
Sigma 56mm F1.4 C is also available in the Nikon Z and Canon RF mounts.
Focal Range
Sigma 56mm F1.4 C is a prime lens with fixed focal lenght of 56mm which has an effective (full-frame 35mm equivalent) focal range of
84mm 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.