The widest-angle RF lens yet produced is coming soon! The RF10–20mm f/4 L IS STM was announced by Canon earlier today. This rectilinearly-corrected zoom will be great for landscapes, interiors, architecture, travel, and videography: a top-quality lens and welcome addition to any EOS R toolkit.
As an L series lens, we know to expect extraordinary optical excellence. Sharpness is de rigueur for L series lenses. Also, Canon has employed their Air Sphere Coating and Sub-wavelength Structure Coating on key lens elements, and among the elements in the lens you’ll find aspheric, UD, Super-UD, and aspheric UD components, all working together to thwart ghosting, chromatic aberrations, and distortion at every turn.
Speaking of distortion: 10mm is very wide. To avoid a fisheye effect, Canon has designed optical and digital (behind the scenes) corrections. Note that your camera may need a firmware update in order to apply the digital corrections, so double check if one is available at the time of release!
Considering the size of comparable EF-mount lenses and the level of optical wizardry contained within, the RF10–20mm f/4 L IS STM sits in an incredibly compact and well-balanced frame. Weighing only 1.25 pounds, it looks like a good option for handheld shooting and for video recording, especially taking the OIS system into account, which is rated for 5 stops of stabilization.
But wait—a surprise feature? The RF10–20mm f/4 L IS STM is the first Canon lens to offer Peripheral Coordinated IS. Thus, the stabilization is rated for 6 stops when used with an EOS R5.
STM stepping motors keeps size and sound down while keeping AF smooth and quick. Minimum focusing distance at all focal lengths is just under 10″—very respectable!