The pentax 50 200mm f4 56 ed wr weather resistant lens features a newly designed simplified weather resistant construction that offers excellent reliability even in rain fog and mist this telephoto zoom lens covers focal lengths from 765mm moderate telephoto to 307mm super telephoto in the 35mm format incorporating an extra low dispersion ed glass optical element in its optics the pentax 50 200mm f4 56 assures excellent description of the subject in various telephoto applications i