Swift Audubon 820 ED 8.5×44



Objective diameter:  44 mm
Magnification:  8.5 x
Exit pupil: 5.2 mm
Eye relief (effective, measured from rim of eyecup): 16.5 mm
IPD: 57  – 73 mm
RFOV:  8.2  degrees = 143 m
AFOV (measured, rounded):  59.5 degrees
Minimum focus distance (measured): 5.55 m
Focus type: CF (direction of rotation from close to infinity: > clockwise)
Degrees of rotation of focus wheel from 5.55 m to infinity (measured): 265 degrees
Range of diopter adjustment (estimate): +/- 2.5 dpt*
Excess travel of focus wheel beyond infinity position (estimate): 6 dpt*
Prism system:  Porro I
Waterproof: splashproof
Weight (measured, with eyepiece cover and strap): 882 g
Made in: Japan
*range of diopter adjustment not affected by position of focus wheel



Over the years, Swift Sport Optics of Colorado, USA, has been selling their “Audubon” porro binocular in a number of different versions; this is the latest model, type 820 ED, on the market since 2011. The image with its wide field of view is bright and shows good contrast, the bridge is more stable than in previous versions, and the Audubon rests very comfortably in your hand – no wonder this binocular has become very popular with birders.


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