Nikon 12x50 Aculon A211 Binocular (Black) Bak-4 porro prism 
 
Optical Performance
Powerful 12x magnification allows for highly detailed observations of distant subjects
Large 50mm objective lenses improve light-gathering ability to ensure distant views remain bright and sharp for better resolution, even in challenging light conditions
Traditional Porro prism light path produces a rich depth of field, allowing the user to discern the relative distances between objects being viewed
High refractive index BAK4 prisms deliver a round exit pupil and a crisp and clear image with limited edge distortion
Aspherical eyepiece lenses correct spherical aberration to produce clear and crisp images, with reduced edge distortion and astigmatism
Anti-reflection multi-coated optics produce neutral and accurate color fidelity, and improve contrast and image brightness
Use and Handling
Large slip-resistant center focus wheel is easy to manipulate, even while wearing gloves
Right-eye dioptric correction compensates for individual user's optical prescription for clearer and sharper views
56-72mm interpupillary adjustment range
Fold-down rubber eyecups for comfortable use with or without eyewear
Tripod mountable with adapter for hands-free use with reduced vibration and arm fatigue
 
Magnification (x)
12
Objective diameter (mm)
50
Real field of view (°)
5.2
Apparent field of view (°)
57.2
Field of view @ 1000m (m/ft)
91/272
Exit pupil (mm)
4.2
Brightness
17.6
Eye relief (mm)
11.5
Close focus ditance (m/ft)
8.0/26.2
Interpupillary distance adjustment (mm)
56-72
Length (mm/inch)
179/7.0
Width (mm/inch)
197/7.8
Weight (g/oz)
910/32.1