The EF 40mm f/2.8 STM from Canon is a sleek and versatile short-normal prime that is ideal for everyday, walk-around shooting. Its f/2.8 maximum aperture helps to realize its slim stature, and also suits working in difficult lighting conditions, and offers control over depth of field for working with selective focus techniques. One aspherical element has been incorporated in the optical design and helps to reduce distortion and spherical aberrations for high sharpness and clarity. A Super Spectra coating has also been applied, which helps to minimize lens flare and ghosting for improved contrast and color fidelity in strong lighting conditions. Short normal-length prime is designed for full-frame Canon EF-mount DSLRs, however can also be used with APS-C models where it provides a 64mm equivalent focal length. One aspherical element limits distortion and spherical aberration in order to realize greater sharpness and accurate rendering. An STM stepping AF motor realizes smooth, near-silent autofocus that is complemented by a rear focus system, advanced AF algorithms, and a high-speed CPU for fast AF performance.
Canon EF 40mm F/2.8 STM Specs