Marine binoculars area of use bird watching travel watersports magnification 7 x lens diameter 50 mm prism system porro exit pupil diameter 714 mm angle of view 68 field of view in 1000 m 118 m twilight factor 187 relative brightness 50 98 focussing system fixed focus viewing straight binocular coating high contrast weight 1 100 g additional functions compass special features for spectacle wearers rubber armouring outdoor function waterpro