There are many tools that are important to the biologist and naturalist, but one of the most useful pieces of equipment that are needed for wildlife field observations is the binocular. Binoculars (Bins) come in different shapes and sizes, and can be purchased at a wide range of prices.
My first pair cost me only $35, but they did not hold up to many of my needs and only lasted for about a year. In general, there are three broad price windows for binoculars, not including the “child’s binocular” that are almost always a gimmick. Some pairs are what I will call cheap. These are in the $50-$100 range. They work fine for those individuals new to wildlife viewing. For example, these “cheap” pairs are great for handing out to visiting eco-tourists on an interpretive walk at a state park. At the other end of the spectrum, there are really expensive binoculars built by companies like Swarovski and Leica that go from somewhere between $1000-$3000. There are even binoculars within this higher range that have built in gyroscopic apparatus used for motion stabilization. For the purpose of this article, I will be focusing on pairs that fall into the “most bang for your buck” range of $200-$400. The quality of this middle price range usually far exceeds the quality of the cheaper varieties, but falls short of the very expensive varieties in ways that only very experienced users will pick up on.
Before purchasing your pair of binoculars, there are a few considerations to make. Without question, you should get a pair that is waterproof. Virtually all varieties that can be purchased at the middle price range of $200-$400 will have this feature. Also, to prevent any internal fogging from some miniscule amount of moisture that has gotten through the waterproofing O-ring, most of the binoculars within this price range will have been filled with Nitrogen gas. Though “Nitrogen-purged” is generally a standard for quality binoculars, it is an important attribute to check before purchasing your set.
The next thing to consider is magnification. Though it might seem intuitive that the higher the magnification, the better, there is a very real tradeoff to consider – the higher the magnification, the more the image appears to shake. I strongly suggest a pair in the range of 7X-10X, that is, images will appear 7-10 times larger that what you see naked eye.
Another important consideration is the width of the objective lens. This variable, along with the magnification variable mentioned, determines how much light is entering your eyes. You will be able to see these two variables written out as a mathematical function on the face of the focus wheel. It will probably read somewhere between 7 X 30 to 10 X 50. The way to interpret this equation requires a basic rule of thumb. Divide the first number into the second number and you will get a number, the light index, somewhere a little above or below 5.0. Your eye naturally has a light index of about 5.0, so if you get a number below the 5.0 standard, you are loosing a little light as compared to your natural sight. An index a little above 5.0 allows you to see more light than your eyes naturally see, allowing you to literally seeing better in the dark.
There are two other qualities that should be checked before purchasing – the close-focus limit and the number of turns possible with the focus wheel. Considering cIose-focus is critical for observing insects like butterflies and dragonflies, and is often very useful when birding as well. I have a pair of bins that have great, very clear optics, but when suddenly needing to change my focus from something close (like an insect) to something far away (like a bird), it often takes so much time to the turn the wheel that the bird will have already flown away. This can be extremely irritating. Catching a glimpse of wildlife is often a fleeting experience, and requires quick reflexes. For this reason, it is a good idea to choose a pair of bins that adjust through the complete focal range (close to infinity) in around 1.5 turns of the focus wheel.
Eagle Optics Rangers
This binocular is my top choice for the price. Depending of the specifications and the company’s regular sales, they can be purchased for between $250 and $400. All together, the Eagle Optics company is excellent. Not only do they have their own quality brand, but they also serve as a warehouse for virtually any brand/model you desire. Also, their brand comes with a lifetime warranty; they have fixed one pair of my bins twice already (minor damage from heat). The Rangers are both water tight and fog-proof. They focus quickly and close (5.2 feet). The magnification I recommend is 8 X, with an objective lens diameter of 42. The equation 8 X 42 will be stamped on the front of the focus wheel.
Zeiss Terra ED
In the optics world, Zeiss is very well known for their quality lenses and general, user-friendly construction. This is a company that has had a hand in many of the innovations that have greatly improved binoculars over the past few decades. As mentioned above for the rangers, I recommend a magnification/objective of 8 X 42, unless you know your personal abilities for using optics well; some folks with very still hands prefer 10 X magnification. These bins have similar specs to the Rangers mentioned above, such as quick focus, close-focus (5.25 feet), water and fog proof, light weight, and sell for around $300.
These bins are going for about $220, and are well worth the price. The general specs are the same as the two above mentioned models, but with an astonishing close-focus of 4.5 feet, making them especially fitting for observing insects that land on your feet! Also as with the above mentioned models, these bins come with a lifetime warranty.
There are several other brands of binocular to choose from, but I’ve picked the above 3 based on price, robust/light weight hardware, and versatility.