Yongnuo 40mm F/2.8 Overview
Distinguished by its pancake design and slightly-wider-than-normal focal length, the YN 40mm f/2.8N from Yongnuo is a compact prime for Nikon F-mount DSLRs. The comfortable field of view of the lens pairs well with the sleek profile to make it an ideal everyday lens to suit photographing in a variety of situations. Its optical design incorporates one aspherical element to reduce spherical aberrations and distortions for greater sharpness, and individual glass elements are also multi-coated to suppress flare for improved contrast. A DC motor affords quick and accurate autofocus performance and a switch lets you quickly change from AF and MF focusing methods. Additionally, a micro-USB port is located on the front of the lens to permit installing firmware updates for the lens.