Confession time: my first high quality, bird-worthy, binoculars were compacts. Yes, it is true - this prime promoter of big aperture did most of his early birding with the original 8x23 Nikon Venturers. When I began to notice the limitations of the inexpensive 10x50's I started my birding career with (I already owned them for astronomy; now I wouldn't use them for that either), I went to the local WalMart to see if I could afford to upgrade to something sharper, lighter, and, well, more satisfying all around. There I sampled the standard chain store offerings - the $35 7x35s and 10x50s in bubble packs; the slightly more expensive (but not noticeably better) boxed binoculars with names at least vaguely associated with quality; and the little roof-prism folding binoculars in green camo that appeal so much to those who don't really want binoculars in the first place, and don't know what they would want if they did.
Nestled among them was a single Nikon 8x23 Venturer. I don't know how it got there. I really was not looking for compacts, and honest, I hadn't read Consumer Reports, I'd never heard of the things, but I picked them up and glanced through them. Whoo . . . what gives? Those little mites blew away the 7x35s and 10x50s on display, and showed the camo roof prism pockets up for what they were (two tubes of eye fuzz on a floppy hinge). Plus, they were the first binoculars I had looked through that had anything like enough eye relief to be comfortable with my glasses. They wanted $79.95 for them! After only a brief struggle with my conscience and my budget, I headed for the checkout.
( A side note for those who don't recall the Nikon Venturer story: Back in the late 1980s, Nikon was coming to the end of their planned life cycle for their Venturer II compact binoculars. They were going to replace them with the first of the Travelite compacts and had announced the end of the Venturers to their dealers. Then, Consumer Reports came out with a compact binocular test report that rated the 8 x 23 Venturer II as the "Best Buy." It was rated as good as, or better than, even some expensive high-end compact roof prisms like Zeiss, with the highest total score of all 25 binoculars tested. Naturally, everybody and their cousin suddenly had to have a Venturer II. The result of the demand was that Nikon went back in production on the discontinued Venturer II and kept making them unchanged for more than four years, until the end of 1993, when the were finally discontinued for the last time. Such is the power of Consumer Reports. )
For the better part of two years I wore those compacts like jewelry. They were around my neck almost all the time. They accompanied me on my first real organized bird walk. I birded Zion and Bryce for first time with them, did my first Christmas Bird Count, made my first pilgrimage to Cave Creek and Ramsey Canyon. I can honestly say I added more birds to my life list with those compacts than I have with any other binoculars I have owned. And, what is more, I attribute a large part of my growth as a birder to owning compacts at the beginning. They were easy to carry and relatively satisfying to use in the field, so they made it possible for me to get in a lot of birding in those first crucial years.
Oh, sure, if I had owned a pair of high quality full-sized binoculars, if I could have convinced myself, at that point, to spend the kind of money I would have had to get them, I might have carried them just as much - and then again, I might not have. Carrying high quality compacts gave me the time I needed to fall in love with a clear, crisp, detailed view of the bird - and quite possibly time to fall thoroughly and irrevocably in love with birding itself.
Of course, the time came when I began to notice the limitations of the compacts, and to wonder if investing in full sized binoculars would give me a better view. By that time, though, I was spoiled. If I was going for full sized binos, they had to be better than the Nikons 8x23s! Thus began my on-going search for the better view, a search that led directly to the essay you are reading.
A final confession: I still dream that one day, against all odds, I will find a pair of compacts, or mid-sizes at the least, that match (or come reasonably close to) the performance that I am now used to in my full sized glasses. I remember all too well the advantages, and the joys, of being able to wear your binoculars like jewelry!
Let's cut right to the real question: should a serious birder even consider compacts? After testing many different models over the years, I'll give you my impressions under several headings.
The Big Plus
The most obvious reason for owning and using compacts is portability. As I said above, there is simply nothing like having binoculars with you all the time, and compacts make that possible. No more decisions about whether to pack the binoculars or an extra change of underwear. For those already loaded down with other equipment, either traveling, or in the field (cameras, tape recorders, video gear), compacts are the obvious solution. Then too, unless you have birded a full day (or several full days in a row) with both compacts and full-sized binoculars, it is hard to imagine the difference 10-20 ounces in weight around your neck (and held at least intermittently up to your eyes) can make in your fatigue factor by the end of the outing. Even the smallest mid-sized binoculars are really "full-sized" when compared, ounce for ounce, with compacts. The difference between 12 and 18 ounces is definitely noticeable by the end of a long day in the field. The bulk issue is more complicated. Some of the smallest mid-sized glasses are not all that much bigger than the largest compacts. The Leica 8x32s and Zeiss 8x30 Diafuns come to mind. If packing space is the problem, you could fit the Leicas into most spaces where, say, the Bushnell 7x26 Customs would go.
The Big Minus
While compacts are easier to carry in the field, that does not make them easier to use in the field. The major culprit here is exit pupil size. I have written extensively, here and elsewhere, about the fallacy of using exit pupil (the size of the circle of light that comes out of the eyepiece) to predict almost anything about binoculars' performance. Here is the one exception to prove the rule. Small exit pupils, such as those produced by compacts, require precise alignment between the binoculars' exit pupil and the pupil of your own eye. Full-sized binoculars, especially in full daylight, are very forgiving about where you put your eye behind the eyepiece. Slight motion of your hands and binoculars is not really disturbing because your small daylight-contracted pupil stays within the large exit pupil of the binos. In fact, the eye/brain automatically compensates for such motion so well that we don't even "see" it.
The slightest motion of compacts, however, often places your eye's pupil outside (or partially outside) the exit pupil of the glasses. Blink! Blink! You shift the glasses around, flex the hinge, maybe pull the glasses away from your eyes and put them back, refocus. When you go through that 4 or 5 times an hour in the field, it can, without your realizing the exact cause, lead to both physical and mental fatigue. The muscles of the eyes get tired. The brain gets tired. You lose visual acuity (and identifications, and enjoyment) because you don't want to look hard any more.
To compound the problem, most compacts are more difficult to focus than most full-sized binoculars. Their limited depth of field means you have to be spot-on to get the clearest view of the bird, while their relatively fast, and often somewhat imprecise, focus makes it hard to hit the spot. Again, the more difficult focus is, the more fatigue you will build up.
Then too, while lightweight binoculars are easier to hold up to your eyes, they are not easier to hold still! The lighter something is, physics tells us, the less force it takes to move it. Compacts bounce around with every breath, every vagrant breeze, and every tremor in your hands (caused not by the weight of the binocular you are holding up, but rather by the weight of your arms that are doing the holding).
Some people find compacts harder to hold on to in the first place than full-sized binoculars. The smallest folding roof prism models can be simply too small for average sized hands. You end up putting extra tension on finger muscles because there is just no easy way to grip the things. Worse yet, focus knobs are often small and you can end up doing finger contortions just to get a decent angle to turn the things. The saving grace is this: if you can find compacts that do fit your hands and face, they are small enough to cup your first fingers firmly against your brow, so that the binoculars become almost a physical extension of your head.
Finally, few compact binoculars yet made will give you the kind of optical performance that you are (or should be) accustomed to in full-sized glasses. Surprisingly, the limiting factor is not brightness. Even 20mm compacts provide enough light to be useful well into twilight. Certainly full-sized binoculars will reach deeper into shadow, even on a bright day, than compacts - and full-sized glasses tend to handle tricky lighting (backlighting, strong side-lighting, etc.) better than compacts - but, in general, you will not be disappointed with a compact's light gathering ability. The limiting factor is distance - or, to put it another way, resolution. The little objectives simply do not have the resolving power of larger objectives.
Close in, within 50 to 100 feet, where many of us do most of our birding, the differences between the compact view and the full-sized view are very subtle (to indistinguishable). Beyond 100 feet, however, most compacts quickly begin to show their limitations. The detail you need and want simply isn't there. Oh sure, you can see the bird. 10x25's give you same size bird at the eye as 10x40s - but the inner detail of feather placement and color simply isn't there in the compact view. At 200 feet, it is difficult to tell a Song from a House Sparrow, let alone a Song from a Lincoln's. You'll find more commentary on these elements of optical performance in the essay "The Ideal Birding Binocular" in the "Basic Education Articles" of this website.
Given all that, I still strongly recommend compacts in four situations:
1.- Beginning birders: There are a number of porro prism compacts on the market that you can buy for under $100 that will give you a real taste of the view that good optics can (and should) provide. For that money, there is really only one binoculars that I can think of that would provide a better view, and, being quite a bit larger and heavier, you might carry it less and actually end up seeing fewer birds. (Not to keep you in suspense, I am talking about the Bushnell NatureView Plus 8x42 porro prism. An exceptional value in full-sized bird-worthy binoculars.) Quality porro prism compacts are an intelligent choice for the beginner who intends to carry glasses all the time and advance rapidly. (Also, being small, porro prisms are also ideal for the younger birder.)
2.- Birders who primarily bird close-in: We are not talking close-in in dense woods or forests here. But, in almost any other situation, if you rarely go after birds that are beyond 100-200 feet, compacts will serve you quite well, and you will not have to cope with the weight and bulk of full-sized glasses. (Dense woodland requires the shadow penetration and contrast handling of full-sized glasses, even when the birds are close.)
3.- Any birder, for back-up or pick-up binoculars: Taking a trip to San Francisco for a conference? Surely there will be time for a pre-breakfast walk along the Bay. Compacts are guaranteed to fit in your luggage. Sometimes forget to grab your big binos on the way out for a Sunday drive with the kids? The compacts in the glove compartment have sorted many an unexpected kettle of hawks and bush of sparrows. Birding in sensitive areas? Urban birding, crowded National Parks, campgrounds, public transport, wharf-side restaurants - anywhere you might not want to be seen with big glasses around your neck (or take the risk of bashing some innocent tourist in the head with them as you track a pelican down the bay). Is there a potential, but binocular-less, birder along on the nature/bird walk with your Saturday group? Grope in the old camera or bird book bag (or purse) and lend him/her your compacts. Oh, you dropped your Swift Audubons (factory repair turnaround one to two weeks) during the height of the warbler migration? Bring on the backup compacts.
4.- Any birder, for secondary birding: There are times for even the most serious birder when we are really out there doing something else. We might be mountain biking, hiking, jogging, collecting wildflowers or butterflies, taking a walk with the spouse, whatever - but we are not primarily birding. Are we going to miss a lifer because we left our binoculars at home? Not if we own compacts. This one applies especially to those of us who have an interest in photography. When you are out photographing birds, you are already carrying too much weight in lenses and bodies and film and tripods and blinds - so compact binoculars can be a real life-saver. (By the way, my own observation is that bird photography and birding are incompatible activities. You are either taking pictures of birds, or you are watching them. You can enjoy both activities, but you can't do both at the same time.)
Compacts fall pretty neatly into four distinct groups.
Unless pocketablity is your only concern, there is really no reason any birder should even look at inexpensive ($50-$125) folding roof prism binoculars. While many are well made, with partial or full multicoatings, rubber armor, fold down eyecups, decent focusing action, a pretty good feel in the hands, and true pocketablity, nothing makes up for the slightly indistinct, slightly foggy, slightly dim view they show when compared to porro prism glasses with the same objective sizes in the same price range. The constraints of the design and the price point do not allow for the kind of optical performance that we need. With the tiny objectives used in compacts, you have to eke out every bit of performance. Any roof prism has to be very precisely made and coated with expensive phase coatings to match the performance of a much less expensive porro prism. The inexpensive roof prisms used in compacts just aren't up to the job. They limit the brightness, resolution, and contrast of the system. When looking at larger objects (big game, varmints, landscapes, etc.) you might not notice the limitations - but birding requires the resolution and definition of extremely small details and subtle colors. Birds are simply too small a target to be satisfying when viewed with inexpensive folding roof prism binoculars. Leave them to the hunters and the tourists. Birders beware (or at least be aware!)
Inexpensive Porro Prism Compacts:
Inexpensive ($75-$125) porro prism compacts, on the other hand, provide some of the best values in today's optical market. Because they are small, and require less material to make, they can be quite inexpensive while still employing high quality materials and workmanship. Nikon Travelites, for example, feature a smooth plastic exterior with finger grips sculpted in. If the sculpting fits your hands (it does mine) they are very secure and comfortable to hold. The Travelites, despite their 25mm objectives, have excellent resolution, thanks to the use of advanced aspheric optics. It is common to find inexpensive porro prism compacts with BAK-4 prisms (the best), at least partial (and sometimes full) multicoatings, aspheric optics, and sturdy light-weight housings with sometimes exceptionally close focusing (for example the Pentax Papilio series that focus as close as 26 inches!) - all in a binocular often selling for less than $100. The result is a truly bird-worth view - a view that can only be improved upon by investing in one of a handful of exceptionally well designed $250 porro prism glasses or $1000 roof prisms.
Expensive Porro Prism Compacts:
There are few expensive ($200-$500) porro prism compacts being made nowadays. However, the Bushnell Custom 7x26 at about $240 is an impressive example of what can be done with compacts if you are willing to spend the money to get everything just about right. The Custom ekes out about all the resolution, brightness, and ease of view that is possible in the compact design. The Custom is the only current compact that I would even consider as my primary birding glass, and, if you can't justify the cost of the expensive roof prism pockets, they are what I would recommend to any serious birder willing to spend the money for back-up, pick-up, or secondary birding.
Expensive Roof Prism "Pocket" Binoculars:
This brings us to the expensive ($400-$700) folding roof prism pocket binoculars from Leica, Swarovski, and Zeiss. Pure elegance! A premium-quality pocket roof prism is a piece of miniature optical craftsmanship designed to be savored by its owner for its own sake, not for what new life species it might reveal during everyday birding. Like the best Swiss (and Japanese) watches, any would be a joy to own, whether its performance was in any way exceptional or not (after all, what does a Rolex do that a Timex doesn't?)
Fortunately, all of these miniature marvels provide optical performance that is nothing to be sneezed at, particularly as the image improvements due to phase-coated optics become the norm in high-end roof prisms. Unfortunately, their performance often can be equaled, or bettered, for half their price in porro prism glasses. Even the best $100 porro prism compacts will give a view that is at least as sharp, contrasty, and bright as the $400 roof prisms - although in a body that is bulkier and non-waterproof. Within the group, 10x25s provide the best resolution and brightness, as long as you can hold them steady enough. That said, a pocket roof prism is not designed to be a serious birder's primary binocular, nor should it be considered as such.
Of the high end pocket roof prisms, I could be tempted to buy any of them (if I could only somehow convince myself it was okay to spend that much money on something that fits in my pocket). Even then, it would be hard to resist the temptation to buy Bushnell Customs and spend the rest of the money on something else. Of course, if money were no object, the sheer elegance of these pocket roof prisms, along with their true pocketablity, waterproofing, and excellent (within limits) optical performance, would make them very nice to own.
So, after all that, if you are considering compacts, keep this in mind: don't think of them as binoculars at all - think of them as a pocket full of birds!
Written by Stephen Ingraham, 1994,
Updated and with additional material by Fred Bieler, 2007