Canon RF 10-20mm F4 L IS STM

This Canon RF zoom covers 10–20mm on full frame, an ultra-wide range aimed at architecture, interiors and wide landscapes. It suits photographers who work in tight rooms or want strong perspective from a camera placed close to a foreground object. It was released in 2023 and remains in production.

The main trade-off is aperture. The f/4 maximum stays constant through the zoom, which keeps exposure simple, but it is modest for dim interiors. Canon RF cameras accept it directly, and it covers the full-frame sensor without a crop.

The lens weighs 1 lb 4.1 oz (570 g). The body is 3.3 in (83.7 mm) wide and 4.41 in (112 mm) long, a manageable size for a full-frame zoom that starts at 10mm. It accepts no screw-in filter at the front, which shapes filter choices. The physical specification scores 93.

The 10–20mm range gives an extremely wide view on a full-frame camera. At 10mm you can frame a whole room from a doorway, or a broad sky above a foreground rock. Zooming to 20mm tightens the composition when the full width is too much. Interior and real-estate shooters will use the wide end most.

Close focusing reaches 0.8 ft (25 cm), so you can set the camera almost against a foreground subject. Nearby objects then appear large while distant scenery stays small, a perspective effect many photographers choose an ultra-wide for. That near-far contrast gives wide compositions their depth. Maximum magnification reaches 0.12x, which gives near foreground objects real presence in the frame.

The f/4 maximum aperture is constant, so the same aperture remains available at every focal length. It is not bright, though, and dim interiors may need higher ISO settings. Stabilisation helps by steadying the camera for handheld frames. Landscape and architecture work often stops down anyway, so the limit matters less there. The optics specification scores 71.

Image stabilisation is built in. It steadies the camera rather than the subject, so it helps most with static scenes such as interiors or evening architecture. In dim rooms or at dawn it supports handheld shooting. It also lets you use slower shutter speeds handheld and keep the ISO lower in fading light.

Weather sealing protects the lens against dust and moisture during outdoor work. That suits landscape and coastal shoots where conditions change through the day. A fluorine coating on the front glass helps water and dirt wipe away more easily afterwards.

There is no zoom lock to hold the barrel at a setting during transport. The features specification scores 78.

Three aspherical elements use specially shaped surfaces that help correct distortion. That matters here, because straight walls and doorframes are common ultra-wide subjects and distortion can bend them.

One Super ED and three ED elements use low-dispersion glass, which helps reduce coloured fringes along high-contrast edges such as skies against rooflines. Internal focusing keeps the lens from extending as you focus.