Binoculars Buying Guide

Illustrated here are roof prism binoculars, one of the two main types of binocs you'll encounter in your search for the perfect pair.
Illustrated here are roof prism binoculars, one of the two main types of binocs you'll encounter in your search for the perfect pair.
©HowStuffWorks 2011

From the beginning of time, humans have always taken a special delight in spying on one another. While you might relate to the thrill of stalking a stranger on the Internet, our early ancestors no doubt enjoyed hiding in the bushes and gasping with glee while their caveman neighbors took part in a private marital spat. Just imagine the joy that must've arisen when, sometime around the 16th century, we discovered that we could snoop on friends and strangers from a distance, with a nifty pair of telescopes put to our eyes.

While it must be conceded that binoculars might not have been invented for nosy Peeping Toms, it's just one more thing we now use binoculars for in the modern age. And we do have a variety of reasons to use binoculars: from birding to astronomy, spotting wildlife to finding fish, getting a good view of Manchester United on the pitch or Kanye on stage, we'll talk about the best binocular bang for your buck.


We'll also explore some of the more interesting uses of binoculars; there's no doubt that our spy movies would be very sad indeed without a good pair of magnifying optics, and we'll see how real-life spy technology has evolved so you, too, can own a $12,000 pair of binoculars (with a few very important caveats, as you'll see).

So let's go ahead and turn our eye to the next page, where we'll learn some of the basics of binoculars so you can spot the pair that will work for you.

What Are You Having: Roof Prism or Porro Prism Binoculars?

You checked out the roof prism pair on the first page. Here's its main competition: Porro prism binoculars.
You checked out the roof prism pair on the first page. Here's its main competition: Porro prism binoculars.
© HowStuffWorks 2011

Binoculars may seem like simple technology, but it's a little more complicated than putting a couple of magnifying glasses to your eyes. Without prisms in the binoculars, which are used to reflect light and turn a magnified image right side up, you're going to be attempting to spot yellow-shafted flickers upside down. As if birding could be even more frustrating.

If you're looking to purchase a pair of binoculars, one of the first decisions you'll have to make is whether you'd like a roof prism or Porro prism pair. What, no burning preference? Keep in mind that binoculars work by using a prism to lengthen the light path between the objective lens (that is, the front lens that captures the light) and the eyepiece. Lengthening the prism, therefore, can increase the magnification without increasing the length of the binoculars.


That works two ways. Porro prism binoculars have objective lens tubes that are offset from the eyepieces; the prisms angle from the eyepieces to the objective lenses. Roof prism binoculars have two straight tubes, making them smaller and more compact.

If you're still not sure if you should buy your "Team Porro" or "Team Roof" T-shirt, there are a few advantages and disadvantages to them. While many assume that Porro prism binoculars are going to be more expensive because they're bigger and more substantial, roof prism binoculars (the straight ones) can actually cost more to make due to the more complicated manufacturing process for the internal angled prism. But beware: Porro prism binoculars usually have a higher quality image and less light loss (which makes the picture clearer). Although roof prism pairs can absolutely have a comparable optic, their compact design and complex prisms make the higher-priced roof prisms a better bet for a quality binocular.

Now that you've had a chance to decide if you want the more compact roof prism binoculars or the less expensive quality of the Porro, let's move on to some of the more specific uses of binoculars and the best buys for them.

Astronomy Binoculars

Good news for wannabe astronomers: You do not need one of the Keck telescopes to frown at the stars and mistake the belt of Orion for the Big Dipper. Turns out, the correct pair of binoculars can be a much easier and affordable way to impress your friends with that one semester of astronomy that you took in college.

If you're shopping for binoculars to check out the planets or stars, there are a few things to keep in mind. First of all, you'll notice binoculars have a couple of numbers -- listed like 7x40 -- that you need to understand. The first number speaks to the magnification; a 7 means that it will look seven times closer than viewing with the naked eye. The second number is called the aperture, which lists the objective lens diameter of the binocs. The larger the aperture, the more light that will enter the lens and provide more clarity to the image.


Astronomy binoculars can rival telescopes in terms of magnification and aperture -- we're talking 30x100 -- to capture more light and make up for distance. These are basically telescopes for each eye, and unless you're looking to spend up to $5,000, you're best sticking to something a bit more modest. To get the most bang for your exploring-the-big-bang buck, do remember that aperture is going to be the most important factor for astronomy binoculars to counteract the dark sky. A safe bet for astronomy binoculars is at least a 7x magnification, and a 40 aperture. Most pairs advertised as "astronomy" binoculars are going to be 10x50, with prices ranging from $70-$400.

Remember that you're going to be holding them to the sky, so for a larger pair, a mount (which can run from $50 for a small pair of binoculars, to $300 for a tripod that can hold a 16-pound, or 7-kilogram, pair) might be a good investment.

Looking at stars and aliens is fun, but for another type of adventure, get yourself out during the day and try to spot a real prize -- a black-headed grosbeak! That's right, fly to the next page to see what binoculars are best for your fishing, hunting and birding enterprises.

Fishing, Hunting and Bird-watching Binoculars

This pair of Pentax waterproof binoculars retails for about $150 and could be handy for your maritime adventures.
This pair of Pentax waterproof binoculars retails for about $150 and could be handy for your maritime adventures.
Image courtesy Amazon

Just like jeans and tube tops, it's pretty obvious when you take a good look at binoculars that one size doesn't necessarily fit all. Different activities will require you to look for some variables in your binoculars, which could have a big effect on your optical success.

Hunting is great example of how buying bigger binoculars is not always better. Consider what you'll be using them for: You'll need a hand-held pair, for instance, that's easy to manipulate and store. Anything above a 10x magnification will probably require a mount, and a spotting scope (a smaller telescope designed for daytime viewing) is going to be more useful if you're looking at something so far out. So while you can spend up to $1,700 on hunting binoculars, you might want to consider a brand like Bushnell or Tasco that has perfectly adequate $70 pairs.


If you're fishing, especially in marine waters, you might be surprised to know that binoculars can be helpful. In fact, many binoculars are really useful for spotting fish or other marine life. When looking for fishing binoculars, remember that ridiculously large magnification is going to be unhelpful. More magnification means that your field of view decreases, which isn't very helpful somewhere as large as, say, an ocean. A large field of view also makes motion more obvious, and thus waves or light reflections can get in the way of spotting something. Sure, there's the 18x magnification binocs for $2,000, but you're probably better spending $100 on the 7x Barska brand -- or even Barska's $40 steal. Just might want to remember to buy those suckers waterproof.

Now, birding without binoculars is like painting with only your eyes. From teeny hummingbirds to eagles and ospreys, being able to see the birds really makes birding a lot more fun. Bird-watching binoculars are much like hunting binoculars, in the sense that an extremely high magnification is not going to help you spot a tiny bird in a big forest. A magnification between 7x and 10x is generally recommended, although with a 7x, you're going to be able see a brighter image and -- in a flock of birds -- more individuals. Choose an aperture between 30 and 50 to get the greatest light capture and spot the prettiest colors on your black-throated green warbler. Anything bigger, and you'll have to rest your arms on something to keep the binoculars steady.

It's absolutely possible to get quality birding binoculars for under $150. Nikon and Alpen both offer affordable prices for decent buys. If you're really interested in spending big bucks, Zeiss and Swarovski have extremely high-quality brands that can go for as much as $3,000.

Still haven't satisfied your need to learn more about binoculars? Take a good look at the next page to get some binocular background and some supercool binoculars for spies working under the cover of darkness.

Night-vision Binoculars and Other Handy Optical Instruments

This pair of night-vision binoculars made by Night Owl retails for close to $500 on Amazon. It comes with 5x magnification.
This pair of night-vision binoculars made by Night Owl retails for close to $500 on Amazon. It comes with 5x magnification.
Image courtesy Amazon

So maybe you're not that into nature, but for good reason: You're a double agent and your covert spying activity doesn't allow you a lot of time under the sun. Good news! You too can benefit from binoculars that allow you to see images while hiding in dark alleys.

Even better? Night-vision binoculars are no longer limited to those employed in secretive government ops. In fact, if you're not looking for anything with a magnification too crazy, you can get night-vision binoculars for less than $400. Keep in mind these binoculars are all mostly lower quality (called "first generation" due to their older technology), and the image won't be too sharp. But if you have the money (or the support of a sovereign nation), keep in mind you can buy second- or third-generation night-vision binoculars that could set you back anywhere from $1,500 to the almost $20,000 Fujinon Stabiscope pair, with infrared vision that can also switch to day vision with 12x magnification. One note: You really do have to be a member of a military or law enforcement agency to buy these more advanced guys.


If your activities are a little more subdued -- more along the lines of soccer games, a Lady Antebellum concert or a nice production of "Die Fledermaus," consider any magnification of 4x or higher (no need to be much more than 8). Aperture isn't going to be as important, unless you're very interested in seeing Beyonce's wedding ring from the third tier of the stadium.

Keep in mind you also might see opera or theater glasses for sale; these types of binoculars are great for stage settings, as they have a wide field of view. They don't have great magnification (somewhere around 5x generally), but their light and compact design are a good fit for shows or events.

If you haven't yet gotten your binocular fix, you're in luck. Take a gander at the next page to learn lots more information about binoculars and which ones are right for you.

Lots More Information

Related Articles

More Great Links

  • Binoculars Information. "History of Binoculars." 2011. (Nov. 17, 2011) Binoculars Guide.
  • "Binoculars Buying Guide." 2005. (Nov. 17, 2011)
  • BirdWatching-Bliss. "Bird Watching Binoculars 101." 2011. (Nov. 17, 2011)
  • Cook, William J. "The Big Five of Marine Binoculars." Captain's Nautical. (Nov. 17, 2011)
  • Garrett Optical. "Binocular Buying Guide." May 24, 2011. (Nov. 17, 2011)
  • Hale, Alan R. "How to Choose Binoculars." C & A Publishing. 1991.
  • Just Binoculars. "Night Vision Buying Guide." 2011. (Nov. 17, 2011)
  • McKean, Andrew. "Binoculars Review: OL Ranks the Best New Binoculars of 2011." Outdoor Life. 2011. (Nov. 17, 2011)
  • Nikon. "At Concerts." 2009. (Nov. 17, 2011)
  • Optics Planet. "Hunting Binoculars." 2011. (Nov. 17, 2011)
  • Shaw Creek Bird Supply. "Binocular Prisms: Roof or Porro?" 2004. (Nov. 17, 2011)
  • Ting, Ed. "Binoculars for Astronomy." Sky and Telescope. 2011. (Nov. 17, 2011)