Binoculars for Sport and Fun!

By Sara Pike, Marketing & Operations Director for Tucson Audubon Society

Have you been considering buying a pair of binoculars? Or how about upgrading from that clunky pair from 1970 that you found in granddad’s attic? Let’s get a conversation started here about binoculars and hopefully this will guide your way forward.

Test and Try binoculars [Sara Pike]

Have you ever just get a better look at that bird high in the tree, or wanted to see the face of the upset coach down on the football field, but were too high up in the bleachers to get a good look? What about getting a closer look at that comet in the night sky? Or how about watching that Elk down in the valley, or getting a better look a wildflower that was just a bit too far into the bushes? Binoculars can be quite fun to use, and they can enhance so much of your viewing of sports, landscapes, the night sky, animals, birds and yes, even bugs and wildflowers!

These days, binoculars come with so many features, and there are so many brands, it may be daunting to get started looking for a new pair. Start by asking yourself what you hope to use them for? Will it be hunting, bird watching, or do you want a small pair to have while hiking? What about just something to take to the sporting event or the theater? Answering this question will help you get started in your search.

Let’s start with some basics here to help you feel more prepared.

A brief history of the binocular, (www.museumofvision.org ):

“The binocular first appeared in the early 1600s as a variation of the telescope. Similar to the early telescope, binoculars were large and hard to use. Modern binoculars - or opera glasses for the theater, field glasses for sport – are largely the result of two innovations in design. The first occurred in 1825 when Lumiere of Paris produced a binocular with an internal screw, centrally placed between two monoculars. This screw allowed the user to focus both eyes simultaneously, thus making binoculars easier to adjust.

The second innovation came from 1870 when Ernst Abbe of the Carl Zeiss Company created the binocular prism. The prism acts like a mirror, which allows a manufacturer to shorten the length of the binocular barrel. Now binoculars could be collapsed to fit into the palm of a hand.”

And today, we have hundreds of styles of binoculars out there, in plenty of sizes, colors and varying qualities to choose from.

Understanding the basics

The style: In your search, you’ll likely see two styles of binoculars, the porro prism and the roof prism. The porro prism binocular is shaped like an “M” due to the two prisms within the barrels being off-set, causing that zig-zag design. Roof Prism binoculars are shaped like an “H” and have prisms that are directly in line, creating a more compact and easier to hold binocular.

Roof Prism design [Sara Pike]

Roof prism binoculars have a more complex light path and require more optical precision in manufacturing (hence the typically higher cost!) and have a protected focusing mechanism. They are typically a sturdier design. Porro prism design is more light efficient, but more difficult to hold and focus, and also has an exposed focusing mechanism allowing for things like sand to muck up the gears.

In your search, you’ll likely see more roof prism design binoculars since these ended up dominating the market due to their more compact design. Either style will provide you with just as much viewing pleasure, though. Testing and trying both will help you decide what feels best in your hands.

The numbers: On every pair of binoculars you’ll see the numbers. They look like “7x35” or “8x42”. What do they mean? Simply remember “Power and Light” and you’ll be set.

The first number is power of magnification. An 8x42 will mean the image you are viewing will be magnified 8 times. The higher you go on the first number, the more magnification power. As the power increases, though, the steadiness of the image becomes compromised and you will see the image shaking more. A tripod is required for higher powered binoculars (Typically 12x and up.)

The second number will let you know how much light gathering power the binocular will have. This number refers to the millimeter size of the objective lens (the lens further away from your eye. The lens that is closest to your eye is called the eye piece.) An 8x42 binocular will have a 42 millimeter size objective lens. The bigger the objective lens, the more light it can gather (ultimately giving you a better image.) But again, be aware that the bigger the objective lens, the heavier the binocular.

Porro Prism design [Sara Pike]

Optimal viewing for the clearest image is typically a millimeter size objective lens that is close to 5 times the magnification. (7x35, 8x42, 10x50.)

The coatings: As light passes through each lens within a binocular, some light is reflected back out ultimately losing some brightness in the image before it reaches your eye. Coatings on lenses help allow more light to get through to your eye. Back in the 1940s, it was discovered that magnesium fluoride did a great job at allowing more light to pass through the lenses. These days, most binocular manufacturers have specialty coatings that are distinct to their binocular line. As you are searching, you will see different coatings named depending on the brand. The better and more complicated the coatings, the brighter and clearer the image you see through the binoculars (and often the binocular will be more expensive, too.) Ask your sales person or search online for the details of the coatings of the binocular you’re interested in.

Close Focus: The Close Focus number you will see with binocular specs is simply how many feet away you’ll be able to focus at the closest point. Those who are interested in looking at butterflies, lizards, wildflowers or backyard bird feeders will enjoy a good close-focus binocular. Today, you can find binoculars that focus up to 4 feet away!

Objective Lens and numbers [Sara Pike]

Field of View: The Field of view is how wide an area you will see through the binocular image. This is typically expressed in the width of feet at 1,000 yards. The field of view is affected by eyepiece design and will usually be narrower with a higher powered binocular. A wider field of view makes it easier to find objects within the view without having to scan around as much.

The importance of testing in person: Eye Relief and Inter-pupillary Distance. Every human face is different! A pair of binoculars that works for your friend may not work for you! Your comfort and ability to see a clear image will depend on a few features about the binoculars.

Eye-relief is how far the eye piece lens sits away from your eye, and can be adjusted by the eye-cups on the binocular. Every style and brand has a different eye-cup relief measurement. Some people have deeper set eyes which will require more eye relief. If you wear glasses, this will require you to adjust the eye-cup relief to fit with your eye glasses.

Inter-pupillary distance is how far the two barrels are able to be pushed together or pulled apart to allow for the light to enter your pupils. If the binoculars cannot be set up to allow light directly into your pupils, you will not get a good, clear image. You will not know this unless you have the pair of binoculars in your hands to try.

These two features tend to be most troublesome for people when using binoculars and least understood at the beginning of a binocular search. If these two features are not working for you, your binocular viewing experience will not be as good as it could be! These two things can only be tested and tried in person, making an online purchase difficult and occasionally frustrating if you receive your new pair and you are not seeing perfectly through them.

Hopefully you are now better equipped to begin your binocular search. Knowing these details can help you feel empowered when searching, and understand a little more when reading about a pair or discussing with a sales person. Good luck!

Talk with binocular manufacturers directly!

Interested in talking directly with a binocular manufacturer? Visit our Southeast Arizona Birding Festival on August 12–14 and you can talk directly with representatives from Swarovski, Zeiss and Opticron at the Vendor Fair. Visit tucsonaudubon.org/vendor.html for hours and details.

Tucson Audubon Nature Shop binocular sales, credit Debbie Honan

Visit the Store!

The Tucson Audubon Nature Shop downtown has one of the best selections of binoculars in town. The volunteers and staff running the shop are well trained and versed in the features of binoculars and can most certainly help you find the right pair. The main Nature Shop is at 300 E University Blvd, #120. Monday – Saturday, 10am – 4pm. Test and try with no pressure to buy. Searching for binoculars is a very personal experience and our volunteers are trained to respect this process.