The Canon EF-S 24mm f/2.8 STM is a compact wide-angle prime lens designed for Canon crop-frame DSLRs. Key features include:
Fast, nearly silent autofocus motor
Excellent general-purpose, walking-around lens
Great value
Crop-Frame Pancake Lens. With a focal length equivalent to 38mm after sensor crop, this ultra-small pancake lens is perfectly suited for smaller DSLRs like the flagship 7D Mark II. The moderately wide focal length makes it a great general purpose, walk-around lens that can be used for all types of photography and video.
STM Autofocus Motor. This stepping autofocus motor provides fast, near-silent performance for both still and video. When used with Canon cameras that feature Movie Servo AF mode, you get continuous autofocus while shooting video (7D Mark II / C300 Dual Pixel / C100 Dual Pixel). Additionally, the aperture is is controlled by a micro-stepping mechanism that translates to near-silent adjustment.
Optics. There’s a single aspherical element in the lens design for minimizing optical aberrations and distortion, while your standard run-of-the-mill lens coatings are used to keep lens flare at bay.
