Exactly What Strength Binoculars Do I Need?

You’ve booked the big safari, packed your clothes, and are almost ready for the big trip.  One important thing remains: getting the right binoculars. 

Binoculars will add to the experience of several activities, which will be covered individually below. But, does it really matters which ones you purchase?  The quick answer is yes if you want to maximize the effectiveness of the binoculars and the enjoyment of your chosen activity. 


The binocular market is projected to get a boost in the next several years due to the rising popularity of outdoor recreation. With increased interest and sales, it can be even tougher to choose the right product. 

This brief overview will help you decide exactly what strength and type of binoculars you really need, depending on your activity of choice!

What Are Those Numbers on the Binoculars?

Perhaps the most important and basic piece of information that is relevant for choosing the strength of binoculars are the numbers listed on each product.  What are they?

They refer to the magnification power and the diameter of the objective lens. Magnification power is really what we mean when we talk about the strength of the binoculars.  

As you might have guessed, it is expressed as a number followed by an “x.” For example, 8×42 means that what you see when you look through the binoculars appears 8 times greater than it would with the naked eye.  

Most of the time magnification between 7x and 10x is usually ideal (with the exception of theater or concerts, for which a lower magnification is better).  We’ll get to more specific activities later. 

Bigger isn’t always better.  Higher magnification will obviously allow you to see further, but this is at the expense of a wider field of view.   

So, if you have a 10x magnification you would see a smaller portion of the same view, but at a closer range, than with an 8x magnification. 

The next number (after the 8x) refers to the diameter of the objective lens, measured in millimeters.  The objective lens is just a fancy way of saying the lens at the end away from your face and closest to the object you’re trying to view.

So, if the product says 8×42, that means that the diameter of the large lens is 42 millimeters. Why is this important? The larger the objective lens, the more light can get in, which results in clearer, brighter, and crisper viewing quality.

The objective lens measurement is also a good way to estimate the total size of the binoculars since that part of the lens is typically the largest part of the whole binocular. In other words, this second number tells you the physical size of the product. 

Other Useful Measurements 

In addition to the magnification and objective lens measurement, there a two other numbers to be aware of as you make a selection: the exit pupil and eye relief measurements. 

It sounds a bit technical, and it is, but there are a few basic ideas that are useful. 

The exit pupil measurement is simply the objective lens diameter divided by the magnification. For our above example, this would be 42 divided by 8 to get an exit pupil measurement of 5.25 mm.  This number is the size of the area of light that actually hits your eyes through the binoculars.

Why is it important? Well, the good news is that most binoculars on the market have an exit pupil of larger than 2mm, which is sufficient for broad daylight.  However, that is the minimum—anything higher will mean a better-lit image.

If you plan to use the binoculars in low light, such as very early morning for hunting, or even areas with a lot of shade or foliage, you will want an exit pupil of at least 5mm. 

The last number to consider is the distance you can hold the binoculars away from your face and still be able to see the full field of view in the lens. This is called eye relief and is primarily a factor if you plan to use the binoculars while wearing glasses.  

Typically, this distance is adjustable within a range, and the largest distance is what is advertised in the specifications.  You’ll want at least 11mm of space to accommodate glasses. 


To review so far, in order to determine how to choose binoculars that are best for your purposes, first consider the magnification and field of view (do you prioritize closer views or a wider angle?) and the diameter of the objective lens since it shows the overall size and larger ones allow more light.

Then, check to make sure the exit pupil is large enough (2mm minimum for standard daylight usage and above 5mm for anything with lower light) and that the eye relief is at least 11 mm if you wear glasses. 

Beyond these basics, there are plenty of other features to think about, which are relevant to specific outdoor activities. Here are some common features:

  • water resistant 
  • waterproof
  • fog proof 
  • zoom lens
  • separate tripod
  • close focusing ability
  • durability / rubber-armored 
  • image stabilizers 

Before you make a purchase, think about the activity you’ll be doing most often, and try to find binoculars with the most appropriate features. Some details follow in the next section. 

Recommendations by Activity

Knowing all the above, it is easier to make some specific recommendations about exactly what strength of binoculars you need, and with what features. 


According to, binoculars are an essential part of hunting, and it’s one of the top reasons people buy binoculars.

For hunting, you will want waterproof and fog proof options, for obvious reasons. You’ll also want very durable binoculars with rubber armored protection in case you drop them while on the move.

The type of hunting will determine the magnification. Generally anything between 7x and 10x, but if you’re hunting from a greater distance, perhaps higher is appropriate. 

Since many hunters take advantage of early morning or evening animal movement, and they are frequently in trees-covered areas, you want to make sure you have an exit pupil measurement of at least 5mm. 

So, for general hunting, look for waterproof, fog proof binoculars with rubber armor durability, with an exit pupil of 5mm or greater, and magnification of 7x-10x. 

Hiking and Backpacking

Similar to hunting, waterproof and fog proof options are best when hiking since you don’t want a little rain to ruin your hike.  In this case, since it is likely you’re carrying a lot of other gear, you’ll want a relatively small pair of binoculars, with an objective lens measurement of 28 mm.  

8x or 10x magnification is fairly standard, and is appropriate here. The pupil exit is less important for hunting since you’ll likely be hiking during broad daylight, but at least 2mm is standard and is sufficient for hiking purposes. 

Wildlife and Safaris

Our recommendation for viewing wildlife is to go with the larger magnification, even if it might be a little jerky from hand movement.  Get the 10x magnification since the wildlife will likely be far away. It’s better not to risk missing out on a good view.  

A mid-size objective lens measurement of about 32mm is good for this purpose, so you are not hauling around a huge piece of equipment.  

Water-resistant or waterproof is a good bonus. 

Boating, Whale-Watching, Paddling

Anytime you are on the water, there is the difficulty of added movement from waves.  Movement makes it harder to use any binoculars, but particularly ones with very high magnification.  A 7x or 8x magnification is good for water activities.  10x is definitely too much. 

To help deal with the movement of waves (or any movement) there are some options that include image stabilizers that counteract unwanted movement and produce a stiller, clearer image. These usually have a gyroscope inside that produces this seemingly magic effect. 

Of course, waterproof and fog proof features are certainly a good idea on the water.

Bird Watching

An 8×42 is the standard recommendation for birdwatching, since it has decent magnification while still allowing for a good field of view.  However, there is also reason to go with a much higher magnification.

It might seem strange, but another use of binoculars can be to see small things close up. So, for viewing small species of birds in detail, at closer distances, magnification of up to 12x is great. A 12×50, for example, is excellent for this purpose.  This is also the activity that you’ll want the close focusing ability.  

Non-Outdoor Uses

For concerts, theater, or other activities that aren’t outdoor-oriented, a compact, low-level magnification of about 3x-5x is recommended.  You’ll keep a larger field of view to see the whole performance, and it is likely you won’t be quite as far away as with other activities.  

Go Forth and Magnify 

Binoculars add a great visual component to several outdoor activities. Take full advantage of the whale-watching tour or safari. Take your hunting skill and effectiveness to another level. Or, simply take in the beauty of your local birds.

With some basic knowledge of specifications and features, you can choose the right option for your favorite activity. 

Before heading out on your next adventure, take a few moments to review the relevant recommendations and specifications from the binoculars experts.  With the right equipment, you’ll be ready to see perfectly what the world has to offer. 

Be sure to check our site regularly for more useful outdoor articles!

Leave a Reply

Your email address will not be published. Required fields are marked *