Opera glasses area of use theatre magnification 6 x lens diameter 15 mm prism system roof suitable for beginner intermediate exit pupil diameter 25 mm min focus distance 3 m angle of view 9 field of view in 1000 m 157 m twilight factor 95 relative brightness 6 25 focussing system central focus viewing straight binocular coating magenta weight 130 g material plastic colour white included in delivery shoulder strap manual special feat