The EF-S 24mm f2.8 STM is a ‘pancake’ prime lens for Canon’s cropped-frame DSLRs with APS-C sensors. It delivers 38mm equivalent coverage which makes it an ideal walk-around lens, roughly similar in length to the classic 35mm options on full-frame or 35mm film bodies. The f2.8 focal ratio gathers more light than a typical kit zoom, and the STM motor ensures smooth and quiet focusing for movies on the latest bodies. But the real selling point of the EF-S 24mm is its size: as a ‘pancake’ lens it’s tiny, transforming your DSLR into a much more portable system. The relatively low price also makes it an ideal second lens for owners of budget DSLRs who fancy trying a general-purpose prime lens instead of a zoom.