The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF 45mm F1.2 and the Sigma 17-40mm f1.8 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 45mm F1.2 with a length of 75mm, is 41mm shorter. On the other hand, the Canon RF 45mm F1.2 has a larger diameter of 78mm 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. Canon RF 45mm F1.2 weighs 346g, which means it is 189g (35%) lighter than the Sigma 17-40mm f1.8 which has a weight of 535g.
Filter Threads
Both the Canon RF 45mm F1.2 and the Sigma 17-40mm f1.8 have the same Filter thread size of 67mm.
Below are links to the 67mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Canon RF 45mm F1.2 and the Sigma 17-40mm f1.8 has the same Canon RF lens mount. Some of the latest released cameras that are compatible with the Canon RF lenses are Canon R6 V, Canon R6 III and Canon C50.
Sigma 17-40mm f1.8 is also available in Sony E , Leica L and Fujifilm X mounts.
Focal Range
Canon RF 45mm F1.2 is a prime lens with fixed focal lenght of 45mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
72mm.
On the other hand, the 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.
