Zoom binoculars area of use travel magnification 8 x lens diameter 25 mm zoom factor 3 times prism system porro exit pupil diameter 313 mm min focus distance 4 m angle of view 46 field of view in 1000 m 80 m twilight factor 141 relative brightness 9 8 focussing system central focus viewing straight binocular coating multi coated weight 350 g special features for spectacle wearers rubber armouring