Canon EF 50mm f/1.8 STM

£120/$125 It’s unfeasibly inexpensive for an own-brand Canon prime lens, but is it any good?

Canon’s EF 50mm f/1.8 lenses have always been attractive budget buys, but the preceding editions felt plasticky, right down to their plastic mounting plate. The more recent STM edition feels more solid and better built, has a metal mounting plate and is richer in features. The old-fashioned electric motor of previous editions is replaced with a stepping motor that’s quieter in operation.

Despite the upgrade, autofocus is a bit sluggish and audible, being noisier than STM systems in most other Canon lenses. That’s because it’s a compact system that uses helical gears to drive focusing, rather than being a lead-screw type. At least smooth autofocus transitions are still enabled when shooting video, and there’s the usual electronic coupling for ‘fly by wire’ manual focusing and manual override of autofocus. The front element extends at shorter focus, but doesn’t rotate when focusing.

Another improvement over the older editions of this lens is there are seven rather than five diaphragm blades, enabling a more well-rounded aperture when stopping down a little. Nevertheless, all other lenses on test have eight or nine blades, potentially enabling an even better rounded aperture.

Performance

The lens is compact and a lightweight at 160g. It definitely punches above its weight in terms of image quality, beating Canon’s 50mm f/1.4 lens for sharpness at apertures between f/1.8 and f/2.8. Levels of colour fringing and distortion are low for both lenses. Overall, this f/1.8 lens is a great buy and unbeatable value at the price.