Magnification 10x 12x 15x 18x
Obj. lens diameter 56mm 56mm 56mm
56mm
Exit pupil 5.6mm 4.7mm 3.7mm 3.1mm
Field of View (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 (%) 92.80%
92.60%
92.50% 92.70%
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
6.1x8.2x2.6
6.1x8.2x2.6
6.1x8.2x2.6
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
Phase Correction Coating Yes Yes Yes Yes
ED glass
Fluorite
Fluorite
Fluorite
Fluorite
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