The 500mm f/5.6 uses low dispersion glass to give superior resolution in a long telephoto design. It can be matched with the 2x Tele Extender for use as a 1000mm f/11 lens. It is relatively portable for its focal length and maximum aperture. Equivalent to 310mm in 35mm format. 500mm f/5.6 Optical Construction 6 elements / 5 groups Angle of View 8 Degrees Minimum Aperture 45 Diaphragm Automatic Minimum Focusing 29� 6.6�/900cm Distance Maximum Magnification 0.07 Ratio Area Covered 24.5 x 33.1� / 622 x 839mm Equivalent 35mm Focal 310mm Length Filter Size 105mm Lens Hood Built in Dimensions (L XW) 14.1 x 4.5� / 358 x 114mm Weight 5lbs. / 2,280g J.P. Code 901090 Mamiya Code 307310