Binoculars are to birding as a shovel is to digging. But they’re more than a utilitarian essential -- they empower us to connect more intimately with birds and all of nature. They are extensions of our eyes, our minds, and even our hearts. When people see a bird well through good binoculars for the first time, they gasp! The experience takes one’s breath away: it is that potent and transformative.

As a birding guide and trip leader, I feel that advice about binoculars is one of the most valuable things I can share. I make a point of checking out participants’ binoculars and how well they’re working for them. Far too often, unfortunately, folks are trying to bird with non-optimal optics. The good news is that, in every price range, the birding-worthiness of the binoculars available today is astoundingly great, even compared with just a couple of years ago. If you’re not seeing all you could be through your binos, consider an upgrade. Your deep appreciation of the birds is far too important to compromise.

That said, here are the most common problems folks have with their binoculars, and how to avoid them.

Too small

When it comes to binoculars, size matters! Tiny compact binoculars are OK for hunters who want to see if that distant object is a buck or a rock. But when you want to apprehend the plumage details of a moving bird, compacts are one step above useless. Their narrow objective lenses (the part that points toward the bird) cannot let in enough light to permit the human eye to see detail. Narrow objectives also radically constrict your field of view, making it difficult to find the birds.

If you keep some compact binos in the car as a backup, wonderful. But they should not be your primary birding binoculars. Binoculars are often described in terms of their magnification and the diameter of their objective lenses in millimeters; e.g. “7x35” means 7-power magnification and a 35mm objective diameter. You want your primary birding binoculars to have objective lenses at least 30mm in diameter, even if light weight is a significant concern. A bit more on both those points later.

Too much magnification

When it comes to magnification, more is less and less is more! More magnification means a narrower field of view and less light getting to your eyes -- so it’s harder to see birds well, especially when it’s not sunny. Higher magnification also increases the relative amount of distortion you’ll see due to your arms jiggling, heat waves rising off the ground, imperfections in the lenses themselves, etc. As a result of all these factors, higher magnification binoculars are more fatiguing to use in the field.

Sometimes you’ll see experienced birders toting top-of-the-line, full-sized binoculars with large objective lenses (40mm or wider) and 10x magnification. But very often these folks also have more versatile, lower magnification binoculars for everyday use. Your primary birding binoculars should have no greater than 8.5x magnification. And if their objective lenses are on the smaller side (30-35mm) strongly consider a magnification of 7x, especially if you have less-than-stellar visual acuity or if your arms tend to shake when you hold the binoculars to your eyes.

You’ve probably picked up on the fact that magnification and the size of the objective lenses create a relationship that greatly impacts binoculars’ usability. Here’s a rule of thumb: in birding-worthy binoculars, the objective lens diameter divided by the magnification should be a number greater than or equal to 4. For the “classic” full-sized birding binocular (8x42), for instance, that value is 5.25.

If most of your birding is feeder watching, you might think “Hey, this doesn’t apply to me. I want all the magnification I can get.” But as soon as a bird leaves the feeders and heads for the bushes, you’re in the same boat with everybody else. Wherever the birds are, you’ll see more detail in almost all circumstances if you go easy on the magnification and thereby enjoy the advantages of better light transmission and wider field of view.

Too cheap

You get what you pay for when it comes to binoculars. More $$s means better glass, more precise alignment, greater durability, and better quality control. This doesn’t mean that you can’t get a pretty darn good birding binocular for well under $200. Likewise, a $500 binocular can be “almost” as good as a $1,500 binocular. But if you’re out there trying to bird with something you paid $50 for, you’re missing out on a big part of the experience. That amount of money just doesn’t get you birding-worthy optics.

Too big

While it’s not as common as the “too small” phenomenon, a good many birders are trying to use binoculars that are too big for their hands and/or faces, or too heavy to be comfortable around their necks for more than a short period. This can lead to frustration and fatigue -- states not conducive to appreciating nature’s subtle beauty.

Today’s technology, driven by the stratospheric popularity of birding, has led to binoculars that are optically superior to older models while weighing significantly less (under 30 ounces in many cases!). If you’re struggling to keep your old-style binoculars steady, consider an upgrade. Be sure to “try before you buy” so you know whether a given pair of binoculars will fit your hands comfortably -- this is very subjective.

Another option is to switch from a conventional neck strap to a harness-style strap. These spread the weight of your binos across your shoulders, reducing neck strain and possibly helping out your arms a little. I also find my optics jostle less when I walk with the harness type straps.

Besides weight, another potential binocular size issue relates to interpupillary distance -- the distance between the pupils in your eyes. Nearly all binoculars are designed for adult men of average proportions. If your eyes are a little closer together than “the norm,” you might not be able to squeeze the two barrels of the binos close enough to fit your face. (If your eyes are wide-set you could have the opposite problem.) Leupold is one manufacturer that has considered a broad range of human ergonomic factors in their designs. In particular, their outstanding new Yosemite 6x30 binoculars are a long-awaited breakthrough for children and others for whom most binoculars are simply too big.

That’s it for this entry -- please stay tuned for more on the topic of “common binocular problems” coming right up.

Peace and good birding,
Scott Cronenweth
www.naturalpathwalks.com