Canon RF 50mm F1.8 STM

Reviewers found it sharp in the centre from f/1.8, superb in the centre by f/2.8, with soft, low-contrast corners until about f/2.8 to f/4 and excellent results across the frame from f/4 to f/8. Distortion is negligible. Uncorrected vignetting is heavy at f/1.8 (about 3.6 EV in one lab test), lateral colour is modest and easy to correct, and bokeh fringing is visible wide open. Image quality falls off at the closest focus distances.

Bokeh is the main optical weakness: highlights are round and smooth in the centre but turn into outlined cat's eyes toward the edges, and foreground blur can look smeary. The STM motor is quiet in video use but not especially fast, and some found it audible; manual focusing makes a whine. Build was judged good for the price and better than the EF version. All agree it is excellent value.

Owners love the size, low weight and price; several call it a great first lens or a go-to lens that rarely leaves the camera, with a useful walk-around focal length. They praise its sharpness, the background blur, low-light use and its close-up performance.

Complaints include a noisy focus motor and, for video, slow autofocus that hunts on moving subjects.