BinocularsBlog – Advice on Digital, Waterproof, & Compact Binoculars for Bird Watching, Sports, Astronomy, Night Vision, & more!

Is it just me or am I getting picky about focusing on a binocular? I can understand a rough focusing, gritty focuser on a cheap binocular, but I expect much more on a premium bino. I look for a bino that is not only fast to focus, but one that is smooth as butter and which leaves little doubt as to when it is in focus. I don't have time to focus one way, then the other when focusing on a bird. I want it in focus, right now. Nor do I want a gritty feeling or high spot or anything else that might distract me when focusing. I want my attention on that bird.

Which is my favorite premium binocular in this regard? Never tested a poor focusing Swarovski EL or Leica Ultravid, but my favorite focuser has to be the Nikon Premier LX. I've tested all sizes of the Nikon Premier LX and have yet to find one that did not please. Focusing has been consistently fast smooth and sure. Nice job, Nikon.

Getting ready to leave for a trip back east to the mountains of north central Pennsylvania for a family reunion and am struggling to decide which binocular to pack. As far as size of binocular, this one is a no-brainer - it will be one of my compact binoculars. Given the trade-off between binocular size and binocular performance, I have no problem with a good compact binocular (and all mine are good). What few birding opportunities I have lost due to the slightly reduced performance of a compact binocular, I have more than offset with the many, many birding opportunities that were possible because I brought one of my small binoculars along, just in case. After all, birds appear in some of the strangest places and at the strangest times. Oh, the stories I could tell.

Right now, I am leaning to my smallest compact bino, the little Leica Ultravid 8x20BR. Hey, it's a Leica and it is definitely as compact as it gets in an 8x20 binocular. On the other hand, when I just grab and go, purely on instinct, I typically reach for my Nikon Premier LX 10x25 binocular. The Nikon Premier is not only in the same class as the Leica Ultravid binocular series, as far as I'm concerned, it also "fits" me better than any compact I own. The Nikon is definitely the most comfortable compact I have used after observing for a full day of birding. I end up with less eye fatigue with this one. The Nikon Premier LX L compact has even unseated my old standby, my Leica Trinovid 8x20 compact binocular.

What's a girl to do? Decisions, decisions.

How good can a binocular be for $39.95? If we are talking about the Bushnell Hemisphere 8x32, I would say surprisingly good. I looked at one the other day as was pleasantly surprised to find that the optics were, in fact, usable. Would I recommend it a serious binocular for serious applications? Of course, not. Would I recommend it for a family on vacation or schools wanting to get some binoculars into the hands of students? Yes, I would. At this price, you could outfit the entire family or classroom and not have to worry if the kids drop the binocular or lose it. I also like the fact the Hemisphere 8x32 has good eye relief and is small enough for kids to handle, well. Don't expect to to buy this version of the Hemisphere 8x32 binocular anywhere else at this price, though. This is an OpticsPlanet exclusive.

If you are looking for a great buy on inexpensive binoculars, check our sale on the Bushnell Hemisphere 8x32 binocular. We just received a special shipment from Bushnell on this one.

Ordinarily, the 8x32 Hemisphere bino is fully multi-coated and is being sold for around $80 by our competition. The version of the Bushnell Hemisphere 8x32 binoculars we just bought from Bushnell is a special run that was only fully-coated (single layer coated), instead of fully multi-coated (multiple layer coated). Okay, special run means Bushnell fell asleep on this production run, but it also means you can now buy two of the fully coated Bushnell Hemisphere binoculars from us for the same price it would cost for only one of the fully multi-coated Bushnell Hemisphere binoculars from the competition. It's a two for one sale - almost.

How much image brightness will this cost you to go with our version, instead of the standard fully multi-coated version of the Hemisphere? The difference between a binocular that is fully coated versus one that is fully multi-coated amounts to about 5-10% in image brightness. (For more information on binocular basics, see my article, How to Understand Binoculars.)

When you consider that most people who buy a binocular at this price are more concerned about price than performance, it makes our OpticsPlanet version of the Hemisphere one of the best buys in an economy binocular on the market. And, no, you won't find it anyplace else. It's an OpticsPlanet exclusive.

A customer asked me, some time ago, to check the color of the objective lenses on several binoculars, all of which were listed as having fully multi-coated lenses. When I asked why, he said that the color of the objective lenses was how you tested to see if a binocular was really multi-coated, compared to only standard (fully-coated). What kind of expert was I?

Okay, fact or myth?

First, I told him to follow up our conversation with my article on the basics of binoculars, How to Understand Binoculars, for a full explanation on binocular lens coatings. I then mentioned that the color you see reflected off the lenses of a binocular can change, depending on the type of light present, the intensity of light present, and especially the angle of light present. All this from one, individual binocular. I invited him to try it for himself.

He was still not convinced, so I told him to visit a local store that had some high end binoculars on display, then compare the colors of the objective lenses, right there in the store. Specifically, I told him to check the color on a Swarovski binocular a Zeiss binocular and a Leica binocular. I told him that I had done this many times and assured him that he would find that each brand had a different color or, at least, a different color tone. Why? High end binoculars use proprietary lens coatings - coatings of each manufacturers own chemical formula. The chemical formulas are different, so the colors vary, though each technically qualifies as multi-coating.

He grumbled that he would try it. I told him to call me back if he could prove me wrong. That was last year. Haven't heard from him since.

Myth busted.

"The larger the second number on a binocular (size of the objective), the brighter the image" is one of the most commonly quoted binocular concepts you will hear. I can't even begin to count all the times I've heard sales people making the image brightness pitch to customers. The bigger the better mentality seems to work overtime on this one. Guess that explains why I sometimes need to get a customer to downsize their binocular choice at times. It also explains why I sometimes encounter folks out in the field struggling with the weight of giant binoculars around their neck. Yes, I actually met a guy out birding once, with a Vixen Giant Waterproof 12 x 80 BCF Binocular around his neck. saw a guy with When I asked why he was carrying such a giant binocular, he insisted that he needed it to get the necessary image brightness for birding in the woods. Fact or myth?

The human eye, of course, can open and close its pupil to control the amount of light that reaches the retina. The diameter of this opening is called the entrance pupil and its size varies with the amount of light in the observer's environment. On a bright sunny day, the entrance pupil may be as small as 1 or 2mm to protect the retina from too much light. Under totally dark conditions, on the other hand, the entrance pupil may open as wide as 7mm (average widest for most humans) to capture as much light as possible, though this maximum shrinks with age. By the time most of us hit our fifties, our maximum entrance pupil may only be 5mm.

On the other side of the equation, we can calculate the size of the beam of light that leaves a binocular's eyepiece. This is called the exit pupil and is simply calculated by dividing a binocular's first number into a binocular's second number. Thus an 8x20 has an exit pupil of 2.5mm and an 8x56 has an exit pupil of 7mm.

When we match up entrance pupil and exit pupil, we begin to understand that bigger does not always mean brighter in a binocular. If you are using a binocular that produces a 7mm exit pupil and your entrance pupil is only at 5mm, your eye cannot use all the light being delivered by the binocular - there is 2mm of exit pupil not entering your eye. In other words, 2mm of light is being wasted. The only time a 7mm exit pupil binocular, such as the excellent Zeiss 8x56 T* FL Victory Binocular will allow you to take advantage of all the light it delivers is when the entrance pupils of your eyes are open to a full 7mm and the only time that will happen is after at least thirty minutes of exposure to total darkenss - twilight doesn't count, here; we are talking total darkness, away from city lights or other light sources. If your in your fifties or older, as we have seen, it may never happen.

For most situations where a binocular is used, then, a binocular with a 4mm or 5mm exit pupil may be all you will ever need, even at twilight or near dark conditions. A better choice in that Zeiss would have been the Zeiss Victory 8x42 T* FL Binocular. It would have produced all the image brightness the most demanding birder would ever need. If you are observing under normal daylight conditions, even a compact binocular with a small an exit pupil of 2mm or 2.5mm will still deliver enough image brightness. Hard to argue with a good compact, such as the Nikon Premier LX compact 8x20 binocular, when size is an issue.

Don't get me wrong; there are some solid optical reasons for going to a large objective (second binocular number), but image brightness is not automatically one of them. Bigger is not atomatically better for image brightness. Myth busted

Roof prism binoculars are better, optically, than the older porro prism design. Right? Must be true because roof prism binoculars typically cost more than porro prism binoculars and all the top dollar binoculars are roof prisms. Fact or myth?

For those who don't know the difference between roof prism binoculars and porro prism binoculars, you can recognize a roof prism binocular by its straight barrel body design and porro prism binocular by its offset body design. For more on the design specifics, see my article at How to Understand Binoculars.

Roof prism binoculars offer a slender body design, which most people find more comfortable to hold and roof prism binoculars also typically offer smoother focusing and, since the focusing mechanism is inside the body and not exposed to the elements. For this same reason, the focusing mechanisms on roof prisms binoculars also typically last longer.

All these roof prism binocular advantages come at a cost, however. An image entering a roof prism is split and when the image is rejoined on the other side, it will be out of phase - some of the wavelengths of light that carry the image are not rejoined precisely. As a result, image sharpness will suffer. The cure for this is a special coating called phase coatings. All but the cheapest roof prism binoculars are now phase coated.

Another optical hurdle that must be overcome with a roof prism is loss of light at a mirror surface which reduces image brightness. In order to combat this, the best roof prisms are coated with ultra high and expensive mirror coatings.

How do porro prisms combat these problems? They don't have to. Porro prisms don't slit the image, so there is no phase problem and they don't use a mirror, so there is no loss of light at a mirror surface. Furthermore, alignment of the prisms is far less critical in a porro prism binocular.

Bottom line is that it is more expensive to make a good roof prism to the same optical standards as a good porro prism. Optically, you get your most bang for the buck with the porro. If you are on a budget and optics are your primary concern, go with a porro. Under $200, I have yet to find a roof prism model that will compare to a porro such as the Nikon Action Extreme 8x40 binocular or Pentax PCF WPII 8x40 binocular and at a bit over $300, the Swift Audubon 8.5x44 porro prism binocular will give many high end roofs a run for their money. Lastly, I will put the Nikon Premier SE 10x42 binocular against any binocular made at any price for its superb optics.

Myth busted.

Let's do an easy one, today.

Some people believe that rubber armoring makes a binocular waterproof or that a binocular needs to be rubber armored to be waterproof. Myth or fact?

Let's look at a couple of binoculars.

First,the Leica Ultravid BL 8x20 binocular. The Leica BL series of binocular is a leatherette covered binocular, not a rubber armored binocular. "Leatherette" is the old fashioned, textured coating that used to be the standard covering on binoculars before rubber armoring became popular. A quick check of the specs shows that the Leica BL is, in fact, waterproof, just like the rubber armored version, Leica Ultravid 8x20 BR binocular.

Let's look at another classic,the Nikon Astro Luxe 18x70 binocular. Like the Ultravid BL, the Nikon is also leatherette covered, not armored and, like the Ultravid BL, it is also fully waterproof.

Okay, myth busted. What's going on?

To make a binocular waterproof it must be sealed internally with O-rings, then all the air removed (air contains water vapor). This is done by forcing nitrogen gas into the binocular (nitrogen gas contains no water vapor) to replace all the air. This process is called nitrogen purging. Simply covering the binocular with rubber doesn't get the job done.

So why armor a binocular? Rubber armoring serves several purposes. It makes a binocular easier to grip (depending on the texture of the armoring)and it also makes a binocular more comfortable to hold in cold weather. Rubber armoring, as you might expect, also protects the binocular from scratches and dings. Lastly, rubber armoring "quiets" a binocular; a rubber armored binocular will not make as much noise when it bangs against another object such as a camera or rifle. This is important for applications requiring an observer to closely approach wildlife.

As a binocular expert, I do my best to educate. If you visit our website at OpticsPlanet.net, you will find a number of binocular articles that explain the basics. These include: Astronomical Binoculars, How to Understand Binoculars and Buy Binoculars, How to Choose a birding binocular, How to Choose a Hunting Binocular, and High Power Observation for Home and Office.

Since I am a big fan of the TV show, Myth Busters, I though it might be fun and useful to continue along this line by using my new blog to bust some popular binocular myths. Today, I'd like to look at the notion that field of view is determined by the size of the second binocular number (objective size). Many beginners believe that the bigger the second binocular number, the larger the field of view (amount of territory) that can be seen when they look through a binocular. Myth or fact?

Let's look at three binoculars and, to keep variables to a minimum, we will use the same series of binocular. We'll go right to the top with a premium series of binocular in the Leica Ultravid binocular. This is as good as it gets in a binocular, so if the Leica doesn't support the myth, no binocular can. The Ultravids we will look at are the Leica Ultravid 8x32 binocular, the Leica Ultraid 8x42 binocular and the Leica Ultravid 8x50 binocular. If the myth is true, the 8x50 should have the largest field of view, followed by the 8x42, with the 8x32 coming in last with the smallest field of view.

A quick check of the specs shows just the opposite is true. The 8x32 has the widest field of view at 400+ feet and the 8x50 coming in last with a field of view of only 350 ft. What's going on?

Field of view in a binocular or any optical instrument is determined by two things.

The first is the magnification (first binocular number). A basic rule of optics is that as magnification goes up, field of view goes down, all else equal. Going to a 10x or 12x Leica Ultravid, then, should reduce the field of view. This is supported by the specs. By the time we hit the 12x Ultravid, our field of view is down to 300 feet. In other words, the first binocular numner is more useful as an indicator of field of view than the second binocular number, but the story doesn't end, there.

The second factor that determines field of view is eyepiece design. There are many eyepiece designs used in binoculars, especially when you get to premium models. These can be very sophisticated, with many lens elements. There are design contraints imposed on eyepiece design by focal length of the optical system as well as physical dimensions of the eyepiece body. Things start to get pretty complex, here.

Okay, myth busted - field of view is not determined by the second binocular number. Bottom line is that you can get a general impression of field of view from the first binocular number, but for an exact number, you need to check the specs. No need to split hairs, though. For nearly any binocular application, a difference in field of view of even 30 feet between two models does not translate into anything significant at typical binocular ranges.

Hi

It's me, Joanie. I will be taking over this blog and adding it my existing Optics blog. Just wanted to let you know in case you visit my Optics blog and don't see as much talk on binoculars. Didn't want you to think I've lost interest in binoculars (fat chance). Since one of the basic rules of optics is that you can't shut Joanie up on the subject of binoculars, I may just blog on binoculars on both sites. This blog, though, will be centered on binoculars.

There will be some changes, here, and those changes will reflect the fact that a hard-core user of binoculars is now writing. I have had over forty years of experience in birding, astronomy, butterfly watching, wildlife observation and nearly twenty years of selling binoculars and writing about them. Let's put it this way - more than one person in my lifetime has threatened to surgically attach a binocular to my forehead since they rarely got to see my face, anyway.