There is a small, select group of binoculars out there that fall into what we might call the "never-fail" class. They are the binoculars you carry when you need to be sure that you are going to see everything that it is possible to see. They are glasses for those times when you need to be sure that if you miss an identification, or even a moment of enjoyment, it is not because your optics let you down.
It is a fairly exclusive group. Most of the members are top of the line $1000 roof prism models. The Swift Audubon 8.5X44 has always stood out in this group like a Yellow-breasted Chat in a flock of Kirkland Warblers. I mean, what is a large, bulky, $200-300 plain old porroprism glass doing in this rare and elite company?
The Swift Audubon has always been something of a odd fellow. In a field where most products must satisfy a wide range of users and expectations, the Audubon was designed for one particular purpose: to give the best possible view of birds in the field under the widest range of conditions, and to do it a price almost any birder can afford. It is a no-apologies birding binoculars, designed for the most demanding birders. The use of oversized porroprisms, large objectives, large complex eyepieces, and a rugged metal body makes the Audubon a handful, but produces an image that is hard to match at any price. Center field resolution is the best of any binoculars we have yet tested by a measure that is clearly visible in the field, especially when the birds get out toward the limits of any binoculars' reach. They have always been my glasses of choice for long distance birding, even over the best 10X models, since the exceptional resolution more than makes up for any benefit you might think you would gain by going to the higher power. The wide field eyepieces provide an exceptional field of view and enough eyerelief to make the Audubons comfortable to use with or without eyeglasses. There is some fuzzyness at the field edge (largly due to coma and curvature of field), and some distortion of straight lines, but since the field edge is used mainly for picking up peripheral birds and following motion, the defects are not objectionable (indeed, they are hardly noticable) in the field. The Audubons have enough light gathering ability to show detail in situations where other glasses fail. They reach far into twilight, of course, but they really come into their own in penetrating deep forest shadow and drawing color and detail out of shadowed areas in high contrast and back lighted situations. Focus is fairly quick and precise and they focus as close as you are likely to get to most birds.
After carrying a pair for five years in the field, I can testify that they do have some limitations. The rubber eyecups, in particular, seem to wear quickly, especially in the folded down position. My Audubons lost optical alignment after about four and half years of heavy use, which included being carried on several mountain bike trips. (Unlike most binoculars, the Audubons can be realigned without disassembly.) Wet weather is a problem as they tend to fog up easily and can end up with enough moisture inside to put them out of action for several days.
Perhaps the worst problem is that the Audubons are simply too heavy to carry comfortably for long on a standard neck strap. Even an hour in the field will fatique neck muscles, and by the end of a CBC you feel like you have been carrying a boat anchor all day. The solution is fairly straight forward: don't use a standard neck strap. The wide "flotation" foam rubber straps (available from the American Birding Association and Optitec) relieve much of the strain, and a shoulder harness removes almost all of it. (See the page 10 on construction your own sholder harness.) I do not find the weight to be a problem in holding the binoculars up to my eyes and steady. If anything, the extra mass of the Audubons, well balanced as it is, makes them more stable, so that arm and hand muscles can actually be somewhat more relaxed than they would be holding a lighter pair of glasses.
If you can live with the size and weight, there are no binoculars on the market today that are easier or more comfortable to use in the field. The large exit pupil, wide and deep field, and particular choice of eyerelief make for a binoculars that are consisantly easy to look through. (See the side-bar for more on eyerelief.) The optics never intrude or get in the way of looking at the birds, and it is, afterall, the birds we are out there to see. To me, that ease of view is the highest recommendation any binoculars can have. I am continually thankful that Swift has managed to provide the easy view in a binoculars that cost as little as the Audubon 8.5X44s do.
The big news this year is, of course, the introduction of the new ED glass model of the 8.5X44. Costing almost twice as much as the standard model on the street, the ED model also offers shower-proofing via rubber "o" rings and seals and full multicoating. The ED glass in the objective does, as you might expect, improve color depth and definition. Colors are slightly more intense, and you can see more different shades and gradiations of the same color. The yellow of a Meadowlark's breast or the blue of a Mountain bluebird's, one solid color through standard binoculars, shows an amazing range of subtly different hues through the ED glass. The improvement, when compared directly to the standard Audubon is very subtle, but definitely there. The effect is probably heightened by the slightly improved contrast that the full multicoating provides. (current models of the ED glass also have improved close focus...ed.)
Is it worth the extra cost? ED glass by itself: probably not -- but since one of the major failings of the Audubon has always been suseptibility to internal fog, the combination of weather-proofing, the extra multicoating and the slight advantage of the ED glass make the new model attractive even at the higher price. At $500, the ED Audubon's are still a bargain when compared to the $1000 roof prisms you would have to buy to equal their performance in the field.
Of course, that makes the regular model simply a steal!