The angled viewing Endurance ED 16-48x68 Spotting Scope from Hawke Sport Optics features high-quality glass with specialized optical coatings to provide clear and bright images. The lens elements are made of Extra-low Dispersion (ED) glass to correct for chromatic aberrations, increase contrast, and improve color rendition. Additionally, they are multicoated to prevent internal ghosting and reflections. To ensure accurate color across the entire visible spectrum, the BAK4 Porro prisms are dielectric coated. These coatings are highly reflective and minimize the loss of light while further boosting contrast and color fidelity. Highly refractive BAK4 Porro prisms minimize spherical aberrations for increased edge-to-edge sharpness and create a better depth of view over roof prisms. This combination of coatings and optics creates a spotting scope that produces bright, clear, highly contrasted images with accurate color transmission. The lightweight magnesium-alloy body is nitrogen-filled and is both water and fogproof. A dual focus system features a coarse fast-focus and a fine-focus wheel. The scope has a tripod mounting shoe that also accepts a 1/4"-20 mounting bolt. A retractable lens shade keeps the Sun or rain off the objective lens. Prism type: Porro Magnification (x): 16-48 Objective lens diameter (mm): 68 Eye Relief (mm): 20 Exit Pupil (mm): 4.25-1.42 Diopter Compensation: +/- n/a Field of view, real (degrees): 2.5-1.2 Field of view at 1000m (m): 43.5-21.5 Minimum focus distance (m): 5 Relative brightness: 18.1-2 Twilight number: 33-57.1 Optical coating: Fully Multi-Coated Size: 404mm Weight (g): 1490