Marine binoculars area of use nature travel watersports magnification 7 x lens diameter 30 mm prism system porro exit pupil diameter 429 mm angle of view 69 field of view in 1000 m 120 m twilight factor 145 relative brightness 18 4 focussing system auto focus viewing straight binocular coating high contrast weight 570 g additional functions compass included in delivery pouch eyepiece lens caps shoulder strap special features rubber armou