Canon RF 50mm f/1.8 STM Lens vs Canon RF-S 10-18mm f/4.5-6.3 IS STM

These cover different focal lengths — the Canon RF 50mm f/1.8 STM Lens is 50mm, the Canon RF-S 10-18mm f/4.5-6.3 IS STM is 10-18mm — so they're not really substitutes. Pick by the field of view you actually need: the Canon RF 50mm f/1.8 STM Lens for short-telephoto / portrait, the Canon RF-S 10-18mm f/4.5-6.3 IS STM for wide-angle.

Choose the Canon RF 50mm f/1.8 STM Lens if you want more light and background blur — f/1.8 is faster than f/4.5, better for low light and subject separation. Choose it if you need more reach — it goes to 50mm vs 18mm for distant subjects, wildlife and sport. Choose it if you prefer a fast, compact single focal length — a 50mm prime over a zoom.

Choose the Canon RF-S 10-18mm f/4.5-6.3 IS STM if you shoot wide — it starts at 10mm vs 50mm for landscapes, interiors and architecture. Choose it if you want one-lens flexibility — a 10-18mm zoom covers what the fixed 50mm can't reframe. Choose it if you like close-focus work — 0.43x magnification vs 0.25x. Choose it if you use filters or shoot video — internal zoom keeps length and balance constant.

Aperture: the Canon RF 50mm f/1.8 STM Lens opens to f/1.8 vs the Canon RF-S 10-18mm f/4.5-6.3 IS STM's f/4.5 — more light and shallower depth-of-field.