Binoculars 101: How to Choose Your Next Pair
Choosing your first pair of binoculars can feel overwhelming. The range of options can seem limitless. Pairs of binoculars with similar specs can differ in price not just by a few bucks, but by thousands of dollars. What makes one pair so drastically more expensive than another? And how do you know which one is really better?
Buying a pair of binoculars is a personal choice. What fits my needs might not fit yours. You want to choose a pair that’s comfortable for you to handle, that works well for your eyes, and at a price point that you can afford. Binoculars are tricky to share and pass around—this is one purchase that it’s okay to be a little selfish over.
Decide on your Budget
For starters, you want to pick a price range that you can afford–and then stretch beyond that just a tad.
While you can pay as little as $20 for a passable pair from a box store, you should expect to spend a couple hundred dollars–at least. Quality costs. Buying binoculars is a long term investment – just like buying a long range optic for your rifle.
If you buy right the first time, you’ll have a piece of quality equipment that will last for decades. I keep my own pair of binoculars in my pack and I never go on an adventure without them. I bought my first—and only pair—in college for $300 and I’ve used them weekly for the last 10 years. They are in excellent shape and hardly show any scars from my many escapades. I’m grateful I bought the highest quality in optics and durability that I could afford.
Consider Your Use
Consider how you plan to use your binoculars. Different uses favor different magnification strengths and binocular sizes.
- Hiking/Outdoors: you’ll want a pair that is rugged (accident proof), easy to carry and light weight. Fine details may not be as important, so you’ll need less magnification and a smaller objective lens. Compact sized binoculars will be best for you. You can use magnification as low as 7x or go as high as 10x. Look for objective lenses no bigger than 30 mm.
- Birdwatching: finer details are very important for accurate bird IDs. You’ll also want a larger field of view, and better light transmission. Birds are most active in the lowlight conditions of dawn and dusk. Birders will want a more standard sized pair of binoculars. 8x or 10x will be plenty of magnification and you’ll want objective lenses bigger than 30mm. Honestly, I don’t like using smaller than 42 mm.
- Hunting/Wildlife: you’ll need a rugged pair of binoculars also 8x to 10x. You’ll want a wide field of view to make spotting and tracking easier.
- Astronomy: you’ll want the biggest set of binoculars you can carry. Bigger barreled binoculars will transmit the most light to your eyes. Look for at least a 10x magnification with 50-56 mm objective lenses.
- A little bit of everything: just get an 8×42 at a price range you can afford.
Magnification & Objective Lens Diameter
You’ll find that all brands use a similar system for model numbers. The first number is the magnification power. It tells you how much closer an image will appear through your binoculars. The second number tells you the diameter of the objective lens, or the diameter of the binocular’s barrel in millimeters.
Let’s look at a pair of Athlon Binoculars. The Midas line has several different models using the numbering scheme we just talked about. Looking at the Athlon Midas G2 8×42 UHD–the “8×42” means the magnification power is 8 and the diameter of the objective lens is 42 mm. There are several more models in this line with magnification powers of 8, 10, and 12, paired with different objective lens sizes.
The objective lens size is an important factor to consider depending on how you plan on using your binoculars. The objective lens size affects how much light is able to enter your binoculars and reach your eye. Bigger objective lenses–barrels–make for a brighter image. This is important if you are using your binoculars in lowlight conditions, like birdwatching or hunting near dawn, dusk, or on overcast days.
However, objective lenses have trade-offs. Bigger lenses are heavier and harder to pack or carry for longer periods of time. Smaller objective lenses may be darker, but lighter and easier to pocket.
Magnification strengths also have trade-offs. While higher magnifications will give you more image detail, they require more light to maintain a brighter image–bigger magnifications will need larger objective lenses to be useful. As you go up in magnification, shakiness from your hands will be more apparent. If you want something greater than 10x, consider using a tripod or skipping binoculars all together and getting a spotting scope.
Eye Relief & Field of View
Eye relief is the distance you need between your eyes and the eyepiece to maintain an image through the binoculars. If you wear glasses, it’s a good idea to look for binoculars that have a longer eye relief (11-15 mm).
Many brands now feature twistable eyecups standard making it easier to finetune the eye relief for days you choose to wear contacts or wear sunglasses.
Field of View
Field of view is the width of an image you can see 1000 yards out from where you stand. Generally speaking, higher magnification powers will have a narrower field of view. High quality optics have been able to compensate a little for this, and higher-end binoculars will have a wider field of view than cheaper ones.
Durability features that used to be found in only the most expensive optics have trickled down to budget options. It’s worth paying for optics with these features:
- Waterproof binoculars are o-ring sealed. This makes them impervious to moisture and can survive a splash in the drink–but not extended submersion (heads up, binoculars don’t float). You want to get binoculars with specs that read “waterproof” not “water resistant.”
- Fog proof binoculars have been nitrogen purged. This means that all the air from inside the binoculars has been removed and replaced with nitrogen. Nitrogen doesn’t contain moisture, so it won’t fog when you move from inside your warm car to the trail.
- Rubberized binocular bodies are easier to grip and it will protect your optics from bumps, bruises and minor scrapes.
Glass prisms will always cost more than plastic ones but the picture quality will be better. Pick the best lens quality that you can afford.
- HD or extra-low density glass is the best option, but you’ll pay for it. HD glass will give you superb image quality and color fidelity. This is what top-of-the-line optics are made from.
- BAK-4 prisms are made of glass, have better light transmission and will give you a better brighter picture. This is the midrange prism option and should be easy to find starting at the $300 price point.
- BK-7 prisms are made from plastic. These are much cheaper and will give you a more squared off looking image. They also aren’t as bright as the other options. On the plus side, these are much more durable than the other two options and are great for rugged use or for kids.
Glass quality isn’t the only feature that can affect price and image quality. Optical lenses are also coated with anti-reflective material to improve light transmission. If you want a good pair of binoculars consider optics that are at least fully coated.
- Coated: one lens has a single layer of coating to improve light transmission. This is the cheapest option.
- Fully Coated: all lenses exposed to air have a single layer of anti-reflective coating.
- Multi-Coated: one lens has a multiple layers of anti-reflective coating.
- Fully Multi-Coated: all lenses to aire have multiple layers of anti-reflective coating. This is the best option and the most expensive.
Porro Prism vs Roof Prism
Old school binoculars have a Porro prism design where the objective lenses are offset from the eyepieces. These are cheaper to make, but are falling out of favor. Most modern binoculars are roof prisms and the objective lenses are inline with the eyepiece. Roof prisms are more compact and easier to pack but also more expensive. If you are torn between a pair of Porro Prism or roof prism binoculars at your price point, pick the Porro prisms because they will have a higher overall quality.
When it comes to making your final pick, go to an optics store and handle as many different pairs as you can. Get a feel for what is comfortable for you to hold and use. Try looking through several different kinds. You might find that there are certain optical quality features that don’t make a difference for you. You might find that the pair that looks amazing on paper, just isn’t a good fit. Or you might realize it’s worth paying a little extra for higher quality optics.
Richard Douglas is a long time shooter, outdoor enthusiast and technologist. He is the founder and editor of Scopes Field, and a columnist at The National Interest, Cheaper Than Dirt, Daily Caller and other publications.