Marine binoculars outdoor binoculars underwater binoculars area of use nature watersports outdoor sports magnification 7 x lens diameter 50 mm prism system porro exit pupil diameter 714 mm min focus distance 76 m angle of view 73 field of view in 1000 m 127 m twilight factor 187 relative brightness 50 98 focussing system individual focus viewing straight binocular coating fully multi coated weight 1 021 g eye relief 18 special features