Marine binoculars area of use bird watching watersports magnification 7 x lens diameter 50 mm prism system roof suitable for expert intermediate exit pupil diameter 714 mm min focus distance 3 m angle of view 67 field of view in 1000 m 117 m twilight factor 187 relative brightness 50 98 diopter correction 3 0 dpt focussing system central focus viewing straight binocular monocular coating multi coated weight 976 g material plastic