Every nature lover should have a good set of binoculars.
For starters, it opens you up to the profusion of wildlife that is all around us, and such a bewildering array of colors, sizes and habits it is, too. Even if you are not a dedicated birder, but merely a wildlife enthusiast, good binos help you get a better glimpse into the lives of animals. Photographers tend to be guilty of preferring to take photos rather than watching. But the fact is, the more time you spend in observation, the more you learn about your subject, which means better photos. And nothing beats a decent pair of binos for observation.
However, selecting a pair of binoculars can be quite daunting - there is a bewildering array of products and prices out there, and selecting becomes very difficult. The purpose of this article is to help you select the right binoculars - binos which will help you appreciate nature, not get in the way.
Most binoculars come in two designs - porro prisms and roof prisms.
Porro prisms are the traditional binocular design: two large cylinders, with the viewing eyepieces offset from the main cylinder & objectives (the front lens elements). The eyepieces tend to be closer together than the objectives. Roof prisms are a more modern design, with two straight, hinged cylinders - the eyepieces are on one end, and the objectives on the other.
Roof prisms are lighter & usually waterproof/fogproof - this makes them more suitable for outdoor use. Porros are bulkier and usually not weatherproof, but have one big advantage going for them - they typically offer better optics ifor the same price range, especially in the budget sector. However, the bulk of the mid to upper-end market is among roof binos, and that is where most of the R&D is happening these days. As such, roof binos are likely to have better contrast & brightness, and comparable sharpness/resolution. So the quality difference has been mostly wiped out except in the absolute entry-level price range.
And for sure, roofs possess all the desirable traits for field instruments: no worry about rain or dust, no worry about condensation as you go from aircon to outdoors, reduced weight for a long day in the field. So unless you are on a very tight budget (<$150)t, consider paying the premium and getting roof prisms.
THE MAIN SPECIFICATIONS
Binoculars typically come with a specification that looks like A x B, where "A" and "B" are numbers. So you have 10x43s, 8x32s, 10x50s and so on.
The first number here refers to the magnification factor of the binoculars - ie, how much bigger does it make the subject appear. The larger the number, the more the magnification of the binocular. The second number refers to the diameter of the objective lens: 32mm, 43mm, 50mm. Basically, this is a measure of how much light the binoculars let in: the bigger the number, the more the light the binocular lets in, but at the cost of size, weight and price.
For nature viewing and birding, you will want binoculars that offer a magnification of between 8x and 10x. While you may be tempted to go for more, don't. Higher magnifications means more shake due to handholding - which in fact reduces clarity and makes it harder to view the subject properly. Anything less than 8x is only for specialized cases - typically, experienced birders with unique needs. At this point, I would not recommend buying less than 8x.
As for the second aspect - objectives - you will most likely want an objective that is between 30mm and 43mm. 50mm is very nice to have, but adds a lot of expense and cost to obtain the same quality - and makes the binos quite heavy, as well. Anything less than 30-30mm becomes a bit too dim. Some people like carrying a pair of 8x20 or 10x25 binos with them, but these are never the "primary" birding/wildlife set and with good reason.
There is also something called "exit pupil" - which is the second number divided by the first. A 8x32 bino has an exit pupil of 4, a 10x43 bino has an exit pupil of 4.3. A larger exit pupil means improved low-light performance.
If you plan to use the binos primarly in bright light, you can settle for a lower exit pupil of around 3. However, for all purpose wildlife and nature use, you'll probably be using them early in the morning or late at night. In that case, try to get an exit pupil of 4 or so, at the very least.
So in summary, for your primary binoculars, you are going to be looking at selecting from 3 specifications: 8x42, 10x42 or 8x32 (and in that category are included the minor variants, such as 8.5x magnifications, and minor variations in objective sizes, like 43-44mm, or 30mm).
So how do you decide which of the above 3 specifications to get?
Well, the most common spec for birding binoculars is the 8x42, or similar variants (8x40, 8.5x44, etc). This gives you a very good combination of magnification, brightness and field of view (in other words, angle of view - which is usually expressed either in degrees or in distance at 1000ft). 8x42s typically have a field of view of 350ft at a distance of 1000ft. For general, all-purpose use, this is a good bino spec to get.
If you have steady hands, you can consider a pair of 10x42 or 10x43s instead. You gain additional magnification, which is helpful when viewing small birds. However, with greater magnification comes reduced field of view - typically, 320ft at 1000ft. The additional magnification is especially handy for viewing raptors, shore birds and for getting closer look at birds that you've already spotted (or been shown). Be aware, however - unless your hands are particularly steady, you may actually see more with an 8x optic, as image shake becomes a serious issue with 10x binoculars.
On the other hand, if you are going to be birding in jungles, or scanning foliage for concealed birds, then you want a wide field of view. In that case, a 8x32 optic is a better idea, as these typically have a field of view of 390-400ft at 1000ft - very wide. This is also a good option if you want a smaller, more compact bino - such as when carrying a bagful of camera gear.
OTHER SPECS & FEATURES THAT YOU MAY WANT TO LOOK INTO
There are a few other considerations worth investigating when choosing binoculars:
Coatings: Manufacturers treat the coatings of their binos to improve contrast and light transmission, and reduce flare. You want binos which have Bak-4 coatings. You also want multi-coated glass - ED elements are even better. Also, while they are not coatings per se, aspherical designs are better than non-aspherical designs, as they provide better sharpness and reduced aberrations.
Minimum Inter-Pupilary Distance (IPD): This is a fancy way of describing the minimum distance between the two eyepieces. If you have a narrow face or your eyes are close-set, you want to make sure you pick binos whose two tubes can be collapsed close enough to match the distance between your eyes
Eye-Relief: This is something that affects people who plan to wear eye-glasses while using binoculars. When you use binos with glasses, the eyepieces are some distance away from your eyes. The eye-relief number basically is a measure of how far you can keep the eyepieces from your eye and still see the full image circle.
Close-focus: This tells you how close the binos focus. Useful if you also want to use the binos for things like watching butterflies and bugs.
Weight: You want a weight that you can carry all day, and which you can hold up to your eyes for long stretches of time. Remember - what seems ok for a few minutes in the store may be anything but ok after a full day of use.
Ergonomics: Some features are hard to quantify. The ergonomics of the grip, balance of the binos in your hand and the tactile feel of the focusing knob are all elements worth considering. However, these are impossible to quantify, as it is a very subjective area. So ideally, you want to try your binos before purchasing them.
OK, ENOUGH ALREADY - JUST TELL ME WHAT TO BUY?
The following are my recommendations for mid-to-full-sized (ie, 8x magnification, and objectives of atleast 32mm or larger) binos in various price categories - except as where noted, most of these binoculars are roofs. Do note that as prices increase, you are paying a large premium for only a minor improvement in performance - once that may not even have a lot of significance in the field.
Porros. It isn't worth buying roof prism binos in this price range. Try before you buy as there tend to be signiicant sample variations in this price range.
Eagle Optics SRTs
Swift Audubon HHS
Vortex Furys/Stokes Broadwing
Leupold Golden Rings
Nikon Superior Es (porros)
Leica Ultravid and Trinovid
Swarovski SLCs and EL
Pentax SP 10x43 - the one I take to National Parks with me, or when I am with a guide
Vortex Viper 8x42 - my main birding bino, especially when I am birding alone
Minox BD 8x32 BR - my all-purpose, carry-everywhere binos, taken along with camera gear or hiking
Keep in mind that ergonomics play a big role in field performance. Poor-handling binos are going to ruin your day in the field a lot more quickly and effectively than binos which are slightly inferior optically but handle great. So as much as possible, try before you buy!
To me, the best bang-for-the-buck is in the $200-$350 range, where you get most of the performance that you need for game/bird viewing in the field. For the budget-conscious, this is the area I would recommend as it gives you fine optics that are well suited for serious use, and which will provide years of service.
Going up a notch, to the $450-600 range gets you noticably better performance, which may be worth it for dedicated users. This is the price point at which you start reaching top-notch optics, which you may never need to upgrade. But now you are starting to get into an area of diminishing returns - beyond this price range, it starts to get very subjective.
Once you start nearing or exceeding the $1000 mark, it is debatable whether or not the actual optics themselves are noticably better in real world usage. However, things like brightness, contrast, flare control, ergonomics, ease of use, etc. may be better. So even though you may not see more, the viewing experience will be better. For example, my Pentax SPs are about half the price of a pair of Leica Trinovids and optically, I couldn't notice any major difference in sharpness or resolution between the two in an A/B comparison in the field. However, the Leicas were much more comfortable to use and were I primarily a "viewer" instead of a photographer, I'd get it in a heartbeat. I may yet get it, come to think of it.
The main thing, however, is how well a pair of binoculars lets you observe wildlife. Once you are spending $250+, I think any binocular from a reputable brand will give you all the necessary details (although the view may be different). So my last word of advice would be - select a price range, select the bino specs and then try a few to see which one feels the most comfortable to use. Buy that one.