This works nicely and it's very precise actually. The product images provide a comparison of the EF-M 22mm f/2 STM (left) to the EF-S 24mm f/2.8 STM (for APS-C EOS DSLRs). You may debate whether the difference in size is significant (percentage-wise that is) but remember that the EF-M lens is a full stop faster and a bit wider! Specifications. Wide Camera Angle. This Canon EF-S 24mm STM lens has amazing camera angles that improve your overall photography. The diagonal, vertical, and horizontal angles are 59.2º, 35º, and 50.5º, respectively. This makes it perfect for capturing all the scenes you fall in love with, making it great for vacations. Source. has a silent focus motor built into the lens. Canon EF 50mm F/1.8 II. Canon EF-S 24mm F/2.8 STM. Lenses with built-in focus motor focus faster and more quietly than lenses without a focus motor which rely on the camera's body focus motor. minimum focus distance. Re: EF-S 24mm f/2.8 STM. It is reasonably fast at f/2.8. What you need to know is whether it is sharp across the FOV and how it does as far as coma. You should also check to see how much it needs to be stopped down before it performs well. If it performs well wide open then great. This means that when you place the 24mm EF-S lens on a cropped sensor (APS-C camera bodies), the image more truly reflects a 38.4mm lens (24mm x 1.6). Therefore, the 24mm EF-S lens is very similar in focal length to the 40mm. On a full-frame camera body, there is no change in the focal length of the lens, so the 40mm remains a 40mm. This item Canon EF-S 24mm f/2.8 STM Canon Single Focus Lens EF50mm F1.8 STM Full Size correspondence EF5018STM Canon Ultra Wide Angle Zoom Lens EF-S 10-18 mm f/4.5-5.6 IS STM APS-C compatible EF-S 10-18 IS STM Canon EF-S 24mm F/2.8 STM Camera Lens Type – Prime lens, Focal Length – 24mm, Focal Length Ranges – Wide-Angle, Lens Mount – Canon EF-S, Max Format size – APS-C / DX, Maximum Aperture – F2.8, Minimum Aperture – F22, Aperture Ring – No, Number of Diaphragm – 7, Optic Elements – 6, Optic Groups – 5, Minimum Focus – 0.16 m (6.3″), Maximum Magnification – 0.27x As already mentioned, the Canon EF 40mm f/2.8 STM uses a stepping motor for AF. AF operations are fairly fast in phase detection AF mode but, frankly, not quite as speedy as a ring-type USM AF - at least based on the EOS 5D II. In a silent environment there's also a noticeable amount of AF noise although it remains unobtrusive. c4XEs9G.