Zoom binoculars area of use watersports magnification 7 x lens diameter 40 mm zoom factor 3 times prism system porro exit pupil diameter 571 mm angle of view 32 field of view in 1000 m 56 m twilight factor 167 relative brightness 32 6 focussing system central focus viewing binocular straight coating multi coated weight 700 g special features rubber armouring