Binoculars 101

Tools designed primarily for viewing scenes rather than capturing them may not be the first thing you think of when you think of Mike’s Camera—it’s in the name, after all!—but we pride ourselves on being experts in all things optical. We stock a variety of quality binoculars, and we’re here to help you choose the right pair for your needs.

So, why would you want to use binoculars as a photographer? And what on earth should you look for when you’re deciding which ones to use? Read on, friends!

How a nice pair of binoculars can help you

We’ll start with the “why” so we have a clearer foundation for “how.”

The most obvious answer, of course, is that sometimes you just want to look at something now, not forever, and binoculars are less-complicated, lighter, and smaller than any camera/lens combo that would provide a similar view. While this is true (and plenty reason to have a little pair on hand), binoculars can also be integrated into your photography workflow.

For one thing, they make a great tool for vetting telephoto compositions. Setting up to capture a very distant image can be a hassle—doubly so if you get all set up, look through the viewfinder, and realize that the bit of treasure you thought would be there is not very impressive at all. Save your neck, back, and tripod manipulation time by taking a quick peek at the scene from afar.

With the right vantage point, you can also use binoculars to scout an area for any kind of photography. Whether if you’re taking wide-angle landscapes, telephoto wildlife portraits, or searching for magical macro subjects, you can get a closer look at details from a distance before you cross a river or whatever. Save the effort, and maybe discover a subject you might not have otherwise noticed!

A note on the numbers

The most obvious specifications you’ll encounter when comparing binoculars are two numbers separated by an “x” (e.g. “10×30”). Without context, these are a little opaque, but the concepts should be crystal clear to any photographer.

The first number is the magnification factor, using non-enhanced human vision as the base. Since a 50mm lens (on a full frame camera) is roughly the same field of view as what you’d see au naturale, that’s your reference point: 8x is like looking through a 400mm lens (on a full frame camera), and 10x like a 500mm lens. A 70–200mm lens would be roughly 1.4-4x in binocular language.

Bear in mind that the longer your magnification, the more difficult hand-holding and getting a steady image will be. The generally accepted wisdom is that you will need additional stabilization when using binoculars with a magnification factor greater than 10x, whether that is a tripod (many binoculars include a standard 1/4″-20 mount) or built-in stabilization like that found in binoculars like the Canon 15×50 IS UD All Weather.

NB! Don’t let similar numbers used to describe compact/fixed-lens cameras confuse you: those lenses are described by their zoom ratio, or the difference between the extremes of the lens. A fixed lens with a 15–45mm equivalent field of view could be described as a “3x zoom” (15 * 3 = 45), whereas a 3x binocular objective would be roughly the same as a 150mm field of view.

The second number is the diameter of the openings where light comes in. The bigger they are, the brighter the image you’ll see, but the more massive the binoculars.

Additional basic binocular theory

There are two main kinds of binoculars on the market: Porro prism and roof prism. Porro prism binoculars are the “classic,” chunky-looking binoculars with each half shaped a bit like that maddening zig-zag Tetris piece. Reflecting by 45 degrees, twice, the binoculars can provide a great reach in a surprisingly compact package while maintaining an optically undisturbed light path. Roof prisms take the same concept even further, using tighter-angled reflection to accomplish the same task as Porro prisms within straight optical tubes.

Ultimately, both Porro and roof prisms can deliver excellent optical results. Given a pair of each providing comparable quality, the Porro prism pair will be larger and the roof prism pair will be more expensive. The ProMaster Modern Classic 7×32 binoculars are a great example of the value you can get in a larger package, so long as you don’t mind lugging that larger package around.

That covers the light-gathering end of the binoculars as well as the internals, but let’s not forget the most tangible part of the experience—the point of contact with your eye! The “exit pupil” is the circle of light at which you will actually be looking. As a general rule of thumb, the more round and crisp this looks when you hold the pair of binoculars up to a light at arm’s length, the more pleasant a viewing experience it will be. You will also want to consider the depth of what’s called the “eye relief,” especially if you plan to wear eyeglasses while using your binoculars. The deeper the relief (the space between the edge of the cup and the glass of the eyepieces) the more comfortable you are likely to be during extended viewing, so long as it is also short enough to allow the exit pupils to fill your field of vision. Larger exit pupils enable longer eye relief.

Desirable features

Once you have an idea of the level of magnification you want and the light-gathering ability you’ll need, you’ll still be faced with a wide range of options. Here are a few more things you’ll want to look for when selecting the perfect pair of binoculars.

• ED (extra-low dispersion) lens elements radically reduce chromatic aberrations, as do lens and prism coatings. “Fully multi-coated” is better than “with multi-layer coatings” which is better than “coated,” which is often single-layer when not specified.
• Dielectric high-reflection coatings are prism-specific and are designed to reduce light loss through the magnification process.
• Phase-correcting coatings are specific to roof prisms, and are important in coating a type of distortion unique to that construction.
• “Waterproof” is good and means what it sounds like.
• “Fogproof” is better. Not only are the binoculars completely sealed, but the interior has been filled completely with either nitrogen or argon gas so that there is no risk of internal condensation when experiencing temperature or humidity changes.
• The aforementioned image stabilization is invaluable when working with high-magnification binoculars, though it carries a price in increased bulk and power requirements.
• On the other end of the spectrum, it may be light weight and limited size that are most valuable to you. The Vanguard Spirit XF 10×42 is a great pair of packable binoculars at a nice price.
• The actual noticeable impact depends on your eyes, but BAK4 is generally considered to be the best material for binocular prism construction.
• It may seem trivial, but design and tactile features matter too. A comfortable grip makes a powerful, palpable difference.

How to focus your binoculars

Once you’ve found the right pair, there’s not much technique in using your binoculars. The only key thing to remember is that you must get them in focus each time a new person is using them. The process varies, but for the vast majority, this is how you do it:

1. Flex the central hinge so that the optics are aligned with your eyes.
2. Identify which eyepiece can be independently adjusted.
3. Close that eye, then rotate the central focus adjustment until it looks right for the eye whose eyepiece can not be adjusted.
4. Close your open eye, open your closed eye, and adjust that eye’s eyepiece until the scene is in focus.
5. Open both eyes. Everything should look great!

Take the leap

That about covers everything you’ll need to know to choose a pair of binoculars you’ll thank yourself for later. If you’d like to compare a few models in person or chat with one of our optical experts, feel free to call or stop by one of our stores at your convenience. We’re always happy to provide our expertise!

Of course, if this guide provided enough information for you to comfortably make a selection, you can browse our catalog by clicking here.

Either way, I hope you found this enlightening and inspiring. Can you think of any times your photographic experience has been enhanced by binoculars? Are you excited about a use I haven’t mentioned here? Tell us all about it in the comments below!