If you’ve ever looked at a pair of binoculars, you’ve seen the numbers printed on them. They might look like a secret code, but they are actually the most important information for choosing the right tool. Understanding what do numbers on binoculars mean is the key to getting a pair that works perfectly for your needs, whether you’re watching birds, enjoying a sports game, or stargazing.
These numbers tell you two critical things: magnification and the size of the objective lenses. They are usually written in a format like “8×42” or “10×50.” Once you know how to read them, you can easily compare different models and pick the best one for your activity. Let’s break down exactly what each part means.
What Do Numbers On Binoculars Mean
The main numbers on binoculars, like “8×42,” consist of two figures separated by an “x.” The first number is the magnification power. The second number is the diameter of the objective lenses in millimeters. Together, they define the binoculars’ core performance characteristics.
Understanding Magnification (The First Number)
The number before the “x” tells you how many times closer the object will appear compared to your naked eye. For example, in “8×42” binoculars, the view is magnified 8 times. An object 800 feet away will look like it’s only 100 feet away.
- Higher Magnification (e.g., 12x, 15x): Brings distant subjects much closer. Great for astronomy or long-range wildlife observation.
- Lower Magnification (e.g., 8x, 10x): Offers a wider field of view, a brighter image, and is easier to hold steady. Ideal for general use like birdwatching, sports, and hiking.
A common mistake is thinking more magnification is always better. Higher power makes hand-shake more noticeable and often results in a dimmer, narrower view. For most people, 8x or 10x magnification is the sweet spot.
Understanding Lens Size (The Second Number)
The number after the “x” is the diameter of the objective (front) lenses, measured in millimeters. In “8×42” binoculars, each front lens is 42mm across. This is a crucial spec because it determines how much light the binoculars can gather.
- Larger Lenses (e.g., 42mm, 50mm): Capture more light, resulting in a brighter image, especially in low-light conditions like dawn, dusk, or forests. They are, however, heavier and bulkier.
- Smaller Lenses (e.g., 25mm, 32mm): Make for compact, lightweight binoculars that are easy to carry. They are perfect for daytime use but may struggle in poor light.
The combination of these two numbers gives you a complete picture of the binoculars’ capability. A 10×50 model will bring things closer than a 8×42, but it will also be heavier. The 8×42 will be brighter and easier to hold steady for extended periods.
Other Important Numbers and Specs
While the main two numbers are the stars of the show, you might see other figures on the binoculars body or in their specifications.
Field of View
This is often expressed as either an angle (e.g., 6.5°) or a width (e.g., 341ft at 1000yds). It tells you how wide an area you can see through the binoculars at a specific distance. A wider field of view makes it easier to follow moving subjects like birds or athletes. Generally, lower magnification gives you a wider field of view.
Exit Pupil
You can calculate this yourself: divide the objective lens size by the magnification. For 8×42 binoculars, 42 ÷ 8 = 5.25mm. This number represents the small circle of light that hits your eye. A larger exit pupil (above 4mm) is better for low-light viewing and makes it easier to keep the full image in view if your eyes aren’t perfectly aligned.
Close Focus
This is the minimum distance at which the binoculars can focus. It’s important for looking at butterflies, flowers, or other nearby subjects. Some models can focus as close as 5 or 6 feet, while others may only go down to 15 or 20 feet.
How to Choose the Right Numbers for You
Now that you know what the numbers mean, how do you pick the right pair? It depends entirely on what you plan to use them for. Here’s a simple guide:
- General Use & Birdwatching: 8×42 is the most recommended configuration. It offers a great balance of light gathering, a wide field of view, and stable viewing.
- Sports & Events: 7×35, 8×32, or 8×42 are excellent. You want a wide field to follow the action and good brightness for both day and night games.
- Hiking & Backpacking: Prioritize size and weight. Look for 8×25, 8×32, or 10×32 models. They are compact enough to carry without being a burden.
- Astronomy & Low-Light: Maximize light gathering. Choose 10×50 or even 12×50. A tripod is highly recommended for magnifications over 10x to avoid shaky images.
- Marine Use: Look for 7×50 binoculars. The 7x magnification is easy to hold on a moving boat, and the huge 50mm lenses provide a very bright image in low-light maritime conditions.
Remember, the best way to choose is to try them if possible. See how they feel in your hands and how the view looks to your eyes. Comfort is a huge factor that specs sheets don’t always show.
FAQ: Common Questions About Binocular Numbers
What does 10×50 mean on binoculars?
It means the binoculars have 10x magnification and 50mm objective lenses. They will make objects appear 10 times closer and are very good for low-light due to the large lenses.
Are 10×42 binoculars better than 8×42?
“Better” depends on use. 10×42 brings subjects closer but has a narrower field of view and is harder to hold steady than 8×42. For most wildlife and general use, 8×42 is often the more versatile and user-friendly choice.
What is the best all-around binocular size?
The 8×42 configuration is widely considered the best all-around size. It provides a strong combination of magnification, light gathering, field of view, and a manageable size and weight for most activities.
What do the numbers on binoculars mean for eye relief?
Eye relief is a separate number, usually listed in millimeters (e.g., 16mm). It’s the distance from the eyepiece lens to where you eye recieves the full image. It’s critically important for eyeglass wearers, who typically need 15mm or more of eye relief to see the whole view.
Is a higher exit pupil better?
Generally, yes, especially in low light. A larger exit pupil (like 5mm from 8×40 binoculars) makes it easier to get a full, bright image and is more comfortable for extended viewing. As we age, our pupils dilate less, so a larger exit pupil can be more forgiving.
By now, you should feel confident about reading those numbers on binoculars. They arent just random digits—they’re a precise description of the instrument’s capability. Knowing what do numbers on binoculars mean empowers you to make an smart choice. You can ignore marketing hype and simply match the specifications to your intended use. So next time you’re shopping, you’ll know exactly what your looking for and why. Grab a pair that fits your needs and start enjoying a closer look at the world around you.