The first Swift Audubon binocular was designed for Swift by Mr. Tamura of the Tamron optical company in Japan from specifications gleaned from a Swift survey of the world’s leading ornithologists. Since then, there have been three versions of the Swift Audubon produced using the same optical formula, which has become world famous for its superior performance and dependability. This newest ED version of the 8.5 x 44mm Audubon is a step up even from the superb optics of the standard Audubon.
This new Audubon uses an objective lens element of the same premium ED (extra-low dispersion) fluorophosphate glass used in expensive camera lenses. This ultra-premium glass gives you 5-10% better contrast and color saturation than the standard Swift Audubon porro prism, without giving up any of that world-famous binocular’s brightness or clarity. In addition, the new Audubon ED adds a new lightweight armored body and waterproofing.
There is much to be said for the Audubon’s 8.5x magnification, compared to the more common 8x. The extra half-power gives you the extra reach you sometimes need to make a positive identification on a distant bird. It also gives you a slightly larger image of a close-in bird to add to your enjoyment. And it does both without adding so much extra magnification that the image becomes hard to hold still enough to see sharply (go much over 9x in a hand-held binocular and the image bounces around with every breath and muscle tremor). The Audubon’s 44mm aperture gives you 21% greater light-gathering than a 40mm bino for images that are bright and high in contrast – even in the low light of early morning or twilight.
The Audubon is a center focus B-body porro prism with premium fully-multicoated BaK-4 prisms for highest light transmission and contrast. The lightweight magnesium body is sealed to be waterproof, although it is not nitrogen-purged and so is not guaranteed to be fogproof in all climate extremes. The Audubon might not survive full immersion for long periods, but it is certainly watertight enough to come in dry when you get caught outside in a heavy rain. It should even survive tropical use with moderate care.
The rubber armor is firm enough for a secure grip, resilient enough for long-term comfort, and lightly textured so your fingers won’t slip. There are provisions for adding an optional tripod adapter #1187 for extended no-hands viewing from a fixed observing location.
The Audubon ED comes with a soft case, a 1.5” wide woven neck strap, twist up rubber eyecups, and objective lens covers. Eyepiece covers are standard, rather than an eyepiece rainguard.
The Audubon’s premium five-element eyepieces give you a wide field of view with relatively little field curvature. The 8.5x Audubon has an excellent delineation of details in the center of the field due to the somewhat higher resolving power of its larger aperture optics vis-a-vis competitively priced 40mm and 42mm binoculars.
The Audubon ED does have somewhat limited eye relief. Eye relief is the distance behind the eyepiece that your eye has to be to see the full field of view. It is important for eyeglass wearers, who can get no closer to the binocular eyepieces, obviously, than the distance between their glasses and their eyes. Swift claims 17mm of eye relief for the Audubon, which should be plenty for an eyeglass wearer. However, while this eye relief is technically correct, the actual usable eye relief of the Audubon ED is closer to 13mm than it is to 17mm, due to the somewhat recessed location of the eyepiece (designed that way to keep eyeglasses from making contact with the eyepiece lens during use, with the possibility of scratching either or both lenses). The 13mm of usable eye relief will somewhat narrow the field of view for eyeglass wearers.
However, this somewhat short eye relief is compensated for by a wider field than competitive binoculars (so wide that it’s almost impossible to see the entire field without looking from side to side – even without glasses). The result is that the usable field of the 8.5 x 44mm Audubon with glasses is often similar to competitive longer eye relief binoculars without glasses.
If you want a little bit more optical performance than is normally reasonable to expect in a porro prism binocular in this price range, the Swift Audubon ED binoculars give you exactly what you’re looking for – at a price well within reach and reason.