Loudoun Wildlife Conservancy

When going out butterfly watching, the key is to have binoculars that can give you good close focus.

Often when we go out on our butterfly walks, the individuals that we’re looking at are just a few feet away and while we may be able to identify them without using binoculars, when you do use them you can see so much amazing detail and color that the butterflies become that much more beautiful.

Some binoculars will focus as close as just 3 feet and this is excellent for butterflies but other excellent models will focus clearly to 5 or 6 feet and this works really well too.

In addition to looking at butterflies, close focus binoculars are great for looking at dragonflies and other insects as well as birds, wildflowers and mushrooms, among other things. There are so many incredible details in nature but we often don’t see because we aren’t focused in on them or are looking too quickly. Looking through binoculars can really help, both to slow us down and to give us the good views we need.

The binocular makers have been working with this for ages so if you wear glasses but also want to use binoculars, not to worry. Many binoculars have either a rubber piece that folds up at the eye piece or the barrel of the eye piece rotates up, giving your eye distance from the glass of the eye piece itself.

The important piece of the puzzle to keep constant is the distance from your eyes to the eye pieces of the binoculars. So, when you select your binoculars, be sure to wear the same glasses that you would wear when you plan to use the binoculars. This will help you make sure that everything fits comfortably.

When checking the specs of the binoculars, check the “eye relief factor”. With wearing glasses, you want to have a long eye relief factor (e.g. 15-23 millimeters). If you have a short eye relief factor (e.g. a few millimeters), when wearing glasses, you will feel like you’re looking through a tunnel and this can give you eye strain and will reduce your field of view.

There’s nothing worse that having that amazing bird fly “right there” into view and you realize that you just can’t see it that clearly because of the dust, raindrops and oils that have built up on your eye pieces or lenses. Keeping your binoculars clean is pretty straightforward but there are a few tips to doing to correctly.

First, you’ll want to remove any debris or dust. The best way to do this is with a blower or fine brush (like those used for camera lenses).

Next, clean the lenses using a soft, lint-free cloth or lens pen. Lens cloths are specially designed with micro fibers which are gentle on lens surfaces. They also don’t leave lint and won’t scratch the glass like a t-shirt or kleenex would. If there are spots or oils on the glass, you can also use special lens cleaning solution like that used for high end camera lenses (but check your binocular manual for guidance on this).

Some definite don’ts for maintaining your binoculars ….never use your breath to moisten the dust before cleaning. It could leave spots or damage the special coating on your lens surfaces. Never use your shirt to clean your optics. No matter how clean and soft your shirt may seem, it will have small particles of dirt on it as well as rough fibers which can leave small scratches that over time will make your lenses appear foggy.

When you’re out in the field and it starts to drizzle, try to keep your binoculars covered. This will help keep those spots off the lenses.

Now then, I better go clean those dirty binos that I showed here in the picture…..

You know the numbers….the 8×42, 10×32, that are printed on the binoculars….so what do they mean? Well, here we are to demystify the numbers. 

The first number (e.g. the 8 in 8×42) refers to magnification. So if it says 8×42 then it means that the object (or bird or butterfly) will seem 8 times closer to you when you look through the binoculars.

The second number is the diameter of the objective lens (the far end of the barrell, not the end you look through) measured in millimeters.  So if you have a metric ruler, you can check this out. Just turn your binoculars around and measure the end that is furthest from where you look through – the number you get will be the same as the second number that your binos are rated as.

So what does all this mean?  Well with magnification there is a sweet spot.  Too little magifiction and you may as well forget using binoculars, too much magnification and the shake of your hands will be too great to be able to enjoy yourself. Typically between 7x-10x is great for going out into the field for general nature watching and birding.

So that takes care of the first number.  The second number (e.g. the 42 in 8×42) is important because the larger the diameter of the objective lens, the more light will be let in – letting you see more in low light conditions, such as dawn and dusk, as well as giving you more light in general to get more clarity and sharpness on your subject.  The down side to the larger diameter is that it also means a larger (and often heavier) binocular.  You’ll want to try out different makes and models so you can “weigh” the trade-offs. Of course with some of the newer lens coatings you can get very bright images with a smaller diameter objective lens but this may also impact the price. 

Lots of tradeoffs here but at least you have one more piece of the puzzle.

So you’re looking at different types of binoculars and run up against yet another factor to consider….lens coating. Lens coating is the super thin layer of fluid that is applied to the glass by the maker of the binoculars.

This special coating reduces the amount of light inside the binoculars that bounces around so that the light goes directly to your eyes. Reducing the amount of light that bounces around makes what you see sharper and brighter, making it that much easier to see the fine details and beautiful colors of the wild creatures that you’re observing.

Many binoculars today will state that they are fully multi-coated (FMC) which means all surfaces of the glass used in the binocular are coated with one or more types of coating.

Today we take for granted that binoculars are a tool of choice when we go out into the field to investigate birds, butterflies, wildflowers or distant landscapes. But when did binoculars actually hit the scene?

Well it started in the 1600s when the first telescopes were invented. Then, people started putting two telescopes together to gain the advantages of binocular vision. In 1618, Galileo constructed a helmet with two telescopes attached and this very well could have been the start of it all.

The first true binoculars (i.e. not attached to a helmet and all) were more similar to opera glasses. Because of their design, however, the magnification was limited and they had very low field of view.

Eventually the prism was invented. And, while this advancement increased both field of view and magnification, it inverted the image…..nothing like trying to id an upside down bird! In 1854, Ignatio Porro came up with the idea of using multiple prisms and then in the 1890s, Carl Zeiss fine tuned the use of porro prisms which are still used today.

Also in the late 1800s (1870s actually), optical engineers were also experimenting with other types of prisms.  The roof prism was invented during this period. This design made for a tougher, more streamlined binocular.

Since the 1800s, there have been great advancements in glass quality and weight as well as lens coatings and other features that have enabled makers to make binoculars lighter. Outside of that though, the basic design has stayed pretty much true to its original form….minus the helmet.

Indeed, there are so many choices out there and the prices range from, under $100 to over $2000. And then, beyond price, the specs range from magnifications of 6x to 25x, and close focus ranges from 3 feet all to way to 20 feet. Then there are prism types and lens coatings to think about.  Its all enough to make you throw up your hands and just go for a nature walk….but it’s so much fun to go on that nature walk with a pair of binoculars…..

So, if you’re looking to buy a pair of binos….the big question is….what makes a good set of binoculars and how do you choose? I recently came across a couple of nice write-ups on this topic so over the next few weeks I’ll cover different aspects and features of binoculars and share what I learned. Today I’ll go over some of the broader features in selecting a pair for general nature adventures and birding. 

The first thing to decide upon is magnification.  Magnification for general nature observation and birding is best in the range of 7x to 10x.  8x is one of the more popular magnifications. Anything lower than 7x and you won’t have enough magnification to make using the binos very worthwhile and anything higher than 10x will be tough to keep steady when hand holding.

I’ll confess that until I was in my late 20s, I avoided using binoculars. I couldn’t understand why people used them. The pair my parents had were a high magnification and heavy and I could never focus on anything because my hands seemed to shake so much and my arms got tired from holding them. It baffled me as to why people went out with these…but then again, the pair at our house mostly sat in their case on a bookshelf. Conversely, the binoculars I had been given when I was younger was a pair of plastic kids binoculars and they wouldn’t focus either. I often wonder now….what if I had been exposed to a “good” set of binoculars when I was a kid…but that’s a post for another day….

After magnification, the next thing to think about is the lens coating. You should select binoculars that are fully multi-coated, meaning that all surfaces of the glass have been coated with the manufacturer’s special secret film. This will add sharpness and brightness to what you are looking at, making it that much better to see the fine details on bird feathers or wings of butterflies and dragonflies or petals on flowers.

The next thing to consider is the quality of the glass. Spend as much as you can afford to get the best glass possible. Ultimately, binoculars are all about the glass since that’s what will produce the image you see. Definitely try out the binoculars that you are considering by going outside of the store so you have real light conditions and try different brands and models side by side to check for sharpness.

The binoculars also need to feel good in your hands and one size does not fit all. Some binoculars are better for larger hands, while others are better for smaller hands. You’ll also want to get a good feel for the focusing ring and how fast it turns.  Some models require many rotations of the focusing knob whereas others focus with fewer rotations. This is a personal preference so you need to try them out.

Another important feature is having binoculars that are waterproof and fog proof. I’ve had the experience myself where we’ve gone out birding and it’s started to drizzle. The birds don’t care, they’re still flitting around, and I don’t care because its a nice warm summer drizzle…but then that yellow-breasted chat finally pops up out of the scrub after chatting and calling at us. We all take in that deep breath of anticipation and the binos go up and then….deflation….nothing but fog on the lens and the bird goes back into the scrub….its such a bummer. This doesn’t happen a lot but it is disappointing when it does.

Other things to consider when selecting binos are good close focus (e.g. less than 6 ft or so is terrific), good eye relief if you wear glasses and general durability of the binoculars. Take a look at the warranty that the manufacturer.  This will give an indication of durability as well as the degree to which the manufacturer stands behind the product.

So, in this economy there may not be a lot of people out buying binoculars but if you are, I hope this helps.