Swift Audubon 8.5x44

The Swift Audubon 8.5x44 (porro version) has been a popular wide angle binocular for the birding market.  The 8.5 power is unusual but an excellent choice, in my opinion, and the 44mm objective is a good compromise from the bulk of a 50mm.  There have been several versions over the years, including ones using special "ED" glass.  Earlier versions were bulkier and had a slightly larger field of view specification (445 ft @ 1000 yards).  I have not examined the earlier versions so I can not comment on their performance.  The latest versions introduced around 2000 have a more ergonomic waterproof body with retractable eyecups.  I have not seen these either but reports are that the optics are essentially unchanged.

Model 804ED

Mfr: J-B56 (no J-E mark)

Date: circa 1990's

AFOV: ~70 degrees

TFOV: ~8.2 degrees, 430 feet at 1000 yards

Eye Relief: ~14mm

Prisms: high index

This is the special "ED" version of the Audubon using extra low dispersion glass to reduce chromatic aberrations.   The objectives appear to be the same as those used in the Celestron 9.5x44ED.  The color rendition is excellent with very pure whites.  The optics are said to be "fully multicoated" (this doesn't necessarily mean that the prisms are multicoated, but the image is very bright).  There is also an "HR/5" marking which I'm guessing stands for a high resolution 5 element eyepiece.  The view is very sharp at the center but is noticeably soft at the edge, a reasonable tradeoff for the wide angle view.   This version has stiff rubber eyecups that fold down.  Unfortunately, the eyepiece lens is recessed and the eye relief is not enough to be comfortably used with glasses.   The new version of the Audubon is supposed to have improved eye relief (but may not, see review below).