I have looked exclusively for a porro-prism desing binocular because of the roof design is not confortable to my face ,it is my fault. Before purchasing the Swift Aubudon 820 ED, I have used a Swarovski Habicht 7x42 porro bino during long years. I was satisfied with it because of its good optical quality, but years comes and I needed better magnification and wider FOV. I have tried out a Swift Audubon 804 modell and I realized that this kind of bino will be my next toy.
Personal explanation againts roofs that I hate the very small deep of field of view that they produce it is a big disadvantage, (at least for me). After checking some top-end roof binos (the big three modells) and thinking about the new pricing of them, I have decided to invest in the new Audubon ED. Its price is far more lower than the top end roof prism binoculars but the optical quality produced is the same. And the optical snobbery is not for me.
But to buy a good quality porro bino is little bit difficult nowadays. Only the Nikon (SE), Swift (Audubon), Minox, Optholyt (Alpin) and Swarovski (Habicht) produce more or less medium priced, top quality porros under 50 mm objective lens. And looking the technical datas, Swift is the winner!
I was surprised how really well reproduces this binocular the colors. For my, it is the best binocular in the field of color-fidelity that I have ever seen (as good as a Zeiss Victory, I compared them side by side). Yellowish or blueish cast is all but existing. No color fringing, the false shining of blue light does not exist.
Very good deep of field of view (like a 7x42 porro bino). The FOV is excellent big (144 m/1000m, bigger than in the case of my other top-end porro 7x42 bino or cheaper 7x50 porro), the distortion at the edges of the view is acceptable.
The easy of view is a crucial point for me. The huge ocular lens surface, the big exit pupil offer very good and easy viewing through the bino.
It has a very big "sweet point", only the outer edge of the view has some fuzzy feeling (like the Zeiss scopes, that disturbe many birdwathers, except keen Zeiss users, like me. I wear glasses but I have not realized any problem with the eye relief, the 16mm is enough (modell 2007). No problem with inner mirroring, only in very bad backlight coditions.
The visualization of the view to the observer's eye is very close, so to watch, observe or follow birds at short distance is easy and very confortable, the binocular's picture has no a wide black frame (tunel vision) like others binos (and to some high-end, too). The design is more comfortable and smaller than in the previous version (Swift 804). Excellent rubber armouring for the waterproofness. Very good close focus point, circa 2 meters! It is a very handy tool.
And why I have to keep back point from the maximum 10?
1. Heavy. It has 890 gramms with neckstrap. OK, weight is not problem for me, but many observer prefer less weight.
2. Awful mechanism for ocular lens bridge. It is balancing countinously between the left and right, loosy, and the intentioned "self balancing" mechanism means "self-adjusment" every minute. Aaaaahhhhgr!
3. Not so good eye cup and diopter adjustment system. At the right ocular, adjusting the diopter means that the eye cup will turn too. I wear glasses and I cannot use the eye cup locking mechanism in the lower position, so for me adjusting diopter correction means tom adjust the eyecup too. How I hate it!
4. Bad quality of cleaning cloth.
But they are relatively small faults. I can accept them and wathing the price and the overall excellent optical performance, I think that it is (one of) the best mid-priced birding binocular with ED-lenses.