RedCat 51 WIFD f/4.9 III

NEW WIFD Version III RedCat Probably the very sharpest 250mm camera lens you will find! Newest version uses the new William Optics Internal Focuser Design (WIFD) 51mm quadruplet ED APO f/4.9 (250mm fl) FPL53 & FPL51 glass  5.25 lbs weight with rings, dovetail, handlebar. >43mm imaging circle with a flat field edge to edge for full-frame sensors Dual Vixen and Arca Swiss Dovetail M48 thread to accept wide t-rings/t-mounts RedCat 51 WIFD III Manual (pdf) Features The best value, highest quality 250mm lens you will find for your camera. 51 mm lens, in a sleek Petzval design, using Synthetic Fluoride (FPL53 and FPL51) glass for a full-frame flat field image. The optical quality provides exceptional performance at a fast focal ratio of f/4.9.  Filter Adapter allows use of 48mm filters. Focusing is made easy with a bahtinov mask integrated into the lens cap.    Specifications Aperture 51 mm (2") Camera/Eyepiece Connection Male M48x0.75 Dawes Limit 0.46 arcseconds Focal Leng