3.5x zoom for super telephoto shooting. When attached to EDG Fieldscope 85/85-A, the focal length ranges from 500 to 1,750mm and when attached to EDG Fieldscope 65/65-A, the focal length ranges from 400 to 1,400mm. FX-format * Available exposure modes: Aperture-Priority Auto and Metered Manual. Available exposure metering: Center-weighted metering * Multilayer coating is applied to all lens elements for brighter optics. * Attaches directly to an EDG Fieldscope and the F mount on a Nikon Digital SLR camera. * Compatible Nikon Digital SLR cameras: D3 series, D2 series, D700, D300 series, D200, D100, D90, D80, D70 series, D5000, D60, D50, D3000, D40 series.