Magnification 10x 12x 15x 18x
Obj. lens diameter 56mm 56mm 56mm
56mm
Exit pupil 5.6mm 4.7mm 3.7mm 3.1mm
FOV 6.5° 5.5°
4.5°
3.7°
Apparent FOV (FOV x Power) 65° 66°
67.5°
66.6°
Field of view (ft/1000 yds) 341 289 236 194
Brightness 31.4 21.8 13.9 9.6
Light transmission (%) 92.90%
92.90%
92.90% 92.90%
Twilight factor 23.7 25.9 29 31.7
Multi Position Eyecups Y/N Yes Yes Yes
Yes
Eye relief 19mm 17.4mm 17.8mm 18mm
Near focus 9.8ft 9.8ft 9.8ft 9.8ft
Eye width adjustment
56~75mm
56~75mm
56~75mm
56~75mm
Dimension WxHxD
6.1x8.2x2.5
6.1x8.2x2.5
6.1x8.2x2.5
6.1x8.2x2.6
Weight 45 oz 45 oz 45 oz 45 oz
Lens constr. obj. 3 groups 4 elements 
groups 4 elements  
3 groups 4 elements 
3 groups 4 elements 
Lens constr. ocular 4 groups 5 elements 4 groups 6 elements 4 groups 6 elements 4 groups 6 elements
Prisms type
Abbe-Koenig
Abbe-Koenig
Abbe-Koenig
Abbe-Koenig
Prism reflective coating type
N/A
N/A
N/A
N/A
ED glass
Flourite
Flourite
Flourite Flourite
Lens coating
Scratch and Oil Resistant
Scratch and Oil Resistant
Scratch and Oil Resistant
Scratch and Oil Resistant
Diopter correction (dpt)
more than +/-2
more than +/-2
more than +/-2
more than +/-2
Pressure tested to what pressure
1m for 30 min. (IPX7)
1m for 30 min. (IPX7)
1m for 30 min. (IPX7)
1m for 30 min. (IPX7)
Storage temperature
-40°~158°F
-40°~158°F
-40°~158°F
-40°~158°F
Functional temperature
-13°~140°F
-13°~140°F
-13°~140°F
-13°~140°F
Frame material
Magnesium
Magnesium
Magnesium
Magnesium
Internal gas purged
Nitrogen
Nitrogen
Nitrogen
Nitrogen
Tripod Adaptable Y/N
Yes
Yes
Yes Yes
Origin
Japanese components assembled in the US
Japanese components assembled in the US
Japanese components assembled in the US
Japanese components assembled in the US