The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon RF-S 18-45mm f4.5-6.3 IS and the Sigma 50mm F2.8 Macro 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 50mm F2.8 Macro is the longer of the two lenses at 67mm. The Canon RF-S 18-45mm f4.5-6.3 IS with a length of 44mm, is 23mm shorter. Besides being longer, the Sigma 50mm F2.8 Macro also has a larger diameter of 71mm compared to the Canon RF-S 18-45mm f4.5-6.3 IS'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-S 18-45mm f4.5-6.3 IS weighs 130g, which means it is 190g (59%) lighter than the Sigma 50mm F2.8 Macro which has a weight of 320g.
Filter Threads
The Canon RF-S 18-45mm f4.5-6.3 IS has a filter size of 49mm whereas the Sigma 50mm F2.8 Macro has a 55mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 49mm filters that we recommend you to consider for the Canon RF-S 18-45mm f4.5-6.3 IS:
And these are the 55mm filters that we recommend for the Sigma 50mm F2.8 Macro:
Lens Mounts
The Canon RF-S 18-45mm f4.5-6.3 IS has the Canon RF lens mount whereas the Sigma 50mm F2.8 Macro has the Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with these mounts are Canon R50 V, Canon R100 and Canon R50 for the Canon RF Mount and Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount.
Sigma 50mm F2.8 Macro is also available in Canon EF , Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Canon RF-S 18-45mm f4.5-6.3 IS has a focal range of 18-45mm and
2.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
28.8-72mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 50mm F2.8 Macro is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 75mm.
