The 7Artisans 55mm F1.4 lens has an optical system containing 6 elements in 5 groups and is based on the Gauss formula. It is a portrait lens designed for APS-C sensor size cameras. Offering a full frame equivalence of 85mm focal length it is also great for close-up portraits. It produces excellent bokeh effect on facial close-ups, half-length portraits, full-length portraits, and has great in-focus sharpness. With this lens, you truly get the best bang for your buck.