We’ve all been there. We open our favorite hunting catalog or head to our favorite sporting goods store to purchase a new pair of binoculars or spotting scope and end up coming home empty-handed because we were simply too confused by all of the numbers to make a confident purchase. What does 10x40mm mean? What do multi-coated lenses do? Why does one pair cost $100 when the pair next to it costs 10 times as much? Selecting good optics can be a daunting task, but with a little research and some basic background knowledge, it isn’t as tough as you might think.
Before buying binoculars or a spotting scope, it’s important to know what all the lingo means. You need to identify and know what you’ll primarily use the optics for. Will you use them to glass a cornfield for deer? Will they be kept on the coffee table to be used for watching birds on the bird feeder? Will you use them for hours at a time on a trip out West to scan the mountainside for mule deer and elk?
It all boils down to two questions: How much money do you want to spend and what are your needs? Alpen Optics’ Vicki Gardner says choosing optics is like picking out a pair of shoes.
“You wouldn’t wear flip flops on a hiking trip and you wouldn’t wear hiking boots on the beach,” she says. “The same is true when it comes to optics. You need to know what you’re going to use them for. Then you need to know what your budget is. Some people will spend $100 on flip flops; some won’t. The same is true when choosing a pair of binoculars. There are a variety of price ranges and options out there, and you need to be educated and know what you’re looking for when you enter the store.”
When looking at binoculars, you first need to know what the numbers mean. Take 7x35mm binoculars, for instance. The “7” means the image will be magnified seven times, and the “35” represents the diameter of the objective lens. So, on a 7x35mm, the objective lens measures 35 millimeters.
If you’re interested in buying a $25 pair of binoculars that will be pulled out of the closet and dusted off once a year, you’ve gained all of the knowledge about binoculars that you’ll need. But, if you want to buy a high-quality pair of binoculars or spotting scope, read on.
Field Of View
Field of view (FOV) is very important when picking out a pair of optics. If you plan on scanning lakes and fields in the Midwest, a standard FOV will do. If you plan on hunting the West, you might want to consider buying a pair of optics with a wide FOV. So what’s the difference between regular FOV and a wide FOV? FOV describes the number of feet per 1,000 yards of distance. So, the FOV for a standard 7x binocular would be 372 feet. If you purchase a pair that has wide angle lenses, FOV goes up to 487 feet. The wider the angle, the more you see as you glass a cornfield or scan the side of a mountain in search of elk. If you hunt a lot, a wide angle lens might be worth the extra investment.
The lens diameter is essential. The amount of light that’s allowed to enter the lens depends on the diameter of the lens; if the lens diameter is large, more light will be able to enter the lens and more light means a brighter image. If you plan on doing a lot of glassing in the late evening or early morning, consider buying a pair of optics that are 42mm or 50mm. The drawback to having a large diameter lens is that they’re considerably heavier than a small diameter lens. If you’re backpacking in somewhere, you might want to get a smaller diameter lens like a 35mm, which will be a smaller, more compact pair of binoculars that weigh almost nothing.
Eye relief is something that needs to be considered when picking out a pair of binoculars, especially if you wear eyeglasses. Eye relief is the distance—expressed in millimeters—from the eye piece lens to the point where the eye is positioned to view the entire image. Eye relief is affected by magnification, the number of lens elements and the field of view. Most binoculars provide 8-13mm of eye relief. Binoculars with long eye relief provide 14-20mm of eye relief. If you wear eyeglasses, you’ll want a pair of binoculars with long eye relief. If you plan on glassing from the side of a mountain for long periods of time, you’ll also want long eye relief. Without long eye relief, you might end up getting a headache that could last all day.
The exit pupil is something you don’t hear many hunters discuss around the campfire, but it’s something you should be aware of before making an optics purchase. Exit pupil is the amount of light that’s usable by a pair of binoculars or a spotting scope. The rule of thumb is the larger the exit pupil number, the brighter the image, especially as the sun dips behind the horizon toward the end of shooting hours. Exit pupil is determined by dividing the diameter of the objective lens by the magnification. For instance, a 7x35mm binocular has an exit pupil of five. For general viewing, anything from 2.5mm to 4mm will work fine. If you plan on using your optics a lot during the evening hours, you’ll want something that’s 4mm or higher. An exit pupil of 5mm is generally considered the minimum for serious hunting situations.
An optic’s resolution is a measure of its image clarity. The larger the diameter of the lens, the clearer the image will be. However, other factors play into how clear an image is. An image’s clarity is obviously important and often, higher-end optics have a clearer image because the companies use higher-quality glass, coated lenses and higher-quality prisms.
The coating on a lens plays a key role in clarity as well. High-quality binoculars always have some form of coating on the lenses. The very best optics are “Fully Multi-Coated,” which means all glass surfaces have multiple coatings on them to prevent them from reflecting or losing light. More coatings are obviously better and all high-end binoculars have multiple coatings. If you’re looking at a pair of optics that say they have been “fully coated,” it means that all air-to-glass surfaces have been coated with at least one layer of coating.
We hear a lot of discussion about prisms. But what are they? There are two types of prisms available in optics: Roof prisms and porro-prisms. Porro-prism binoculars tend to be larger and have a unique body design. Roof-prism binoculars tend to be more straight and streamlined. Both types, if manufactured correctly, work well.
Now that you know what all of the optics terminology means, how do you know which pair of optics is right for you? Binoculars are like everything else out there and a lot of it boils down to personal preference. And, of course, you generally get what you pay for. If you plan on using a pair of binoculars a lot or plan on taking them all over the country on hunting trips, you should purchase a high-quality pair of optics that are waterproof, fog-proof, have good eye relief and have multi-coated lenses.
There are binoculars that meet those requirements in the $150 range and there are others that will have no problem pushing you into the $2,000 range. The high-end, German-made binoculars often separate themselves from the competition by offering optics that have the best glass available on the market. They’re tough, rugged and will last a lifetime. And their performance is incredible. However, I’ve looked through both $500 optics and $2,000 optics, and depending on the manufacturer, I have noticed very little difference. An optics expert might be able to see the difference, but chances are the average Joe can’t.
As you look for a new pair of optics this year, look for a pair that fits your needs and has many of the features outlined above. If you want most of the features mentioned here and want a pair of binoculars that will last a lifetime, you should plan on spending a minimum of a few hundred dollars. When researching brands, don’t count anyone out and don’t base your purchase on price alone. Try out each pair and then decide which one is best for you.
For more information on the author, visit TracyBreen.com. For more information on Alpen Optics, visit Alpenoptics.com.