If you’ve ever picked up a pair of binoculars, you’ve probably wondered what the numbers on binoculars mean. Those figures, like 8×42 or 10×50, are the key to understanding their performance and choosing the right pair for you.
They might look like a secret code, but it’s actually very simple. These numbers tell you about magnification and light gathering ability. Getting to know them will make you a much more informed shopper and user.
What Are The Numbers On Binoculars Mean
The main numbers you see, such as 8×42, consist of two parts. The first number, before the “x,” is the magnification power. The second number, after the “x,” is the diameter of the objective lenses in millimeters. Let’s break down what each of these means for your viewing experience.
Magnification Power (The First Number)
The magnification number tells you how many times closer the object will appear compared to your naked eye. For example, in 8×42 binoculars, everything looks eight times closer. A bird 80 feet away will seem like it’s only 10 feet away.
Higher magnification isn’t always better. While it brings things closer, it also amplifies any hand shake, making the image shakier. It also narrows your field of view. Most general-use binoculars use magnifications between 8x and 10x.
- 8x Magnification: Excellent for general wildlife, sports, and boating. Offers a wider field of view and a steadier image.
- 10x Magnification: Great for long-distance viewing, like for open landscapes or large stadiums. Requires a steadier hand or support for best results.
- 12x and Above: Typically used for specialized viewing like astronomy or extreme long-range observation. A tripod is highly recommended.
Objective Lens Diameter (The Second Number)
The second number is the diameter of the large lenses at the front of the binoculars, measured in millimeters. These lenses gather light. A larger number means bigger lenses that can collect more light, resulting in a brighter image, especially in low-light conditions like dawn or dusk.
However, bigger lenses also mean a heavier and larger binocular. You need to balance brightness with protability.
- 20mm to 25mm (Compact): Small, lightweight, and easy to carry. Image brightness can suffer in low light.
- 30mm to 40mm (Mid-Size): A popular compromise. Good light gathering for daytime use without being to heavy.
- 42mm to 50mm (Full-Size): Excellent for low-light conditions. These are the standard for serious birding and wildlife observation, but are bulkier.
- 50mm and Above: Maximum light gathering for astronomy or marine use. Often require a tripod due to their size and weight.
Putting It All Together: Examples
Let’s look at some common configurations and their best uses.
8×42 Binoculars
This is arguably the most versatile configuration. The 8x power gives a steady, wide view, and the 42mm lenses provide plenty of light for most daytime and early evening situations. It’s the top choice for birdwatchers, hikers, and sports fans.
10×42 Binoculars
These offer more reach for detail at distance, like identifying an animal across a valley. They share the same light-gathering ability as the 8×42, but the higher magnification requires a steadier hand to avoid a shaky image.
10×50 Binoculars
These are a fantastic low-light pair. The 10x magnification brings subjects close, and the large 50mm objective lenses make the image very bright. They are heavier, but ideal for hunting during twilight or stargazing.
Other Important Numbers and Specs
While the main two numbers are crucial, you might see other figures on the binoculars body or box.
Field of View
This is often expressed as feet at 1,000 yards (e.g., 330 ft/1000yds) or degrees. It tells you the width of the area you can see through the binoculars. A wider field of view makes it easier to follow moving subjects, like birds in flight. Generally, lower magnification means a wider field of view.
Exit Pupil
You can calculate this yourself: divide the objective lens diameter by the magnification. For 8×42 binoculars, 42 รท 8 = 5.25. The exit pupil is 5.25mm. This number shows how much light reaches your eye. A larger exit pupil (over 4mm) is better for low-light use and makes it easier to find and maintain the image.
Close Focus
This is the minimum distance at which the binoculars can focus. If you enjoy looking at butterflies, flowers, or insects, a close focus of 6 feet or less is very usefull.
How to Choose the Right Numbers for You
Think about your primary activity. Your main use will guide your decision on the best magnification and lens size combo.
- For Birdwatching & General Wildlife: 8×42 is the gold standard. It offers a great balance of light, detail, and stability.
- For Sports Events: 8×32 or 8×42 are excellent. You get a wide view of the field and enough detail from stadium seats.
- For Hiking & Backpacking: Prioritize weight. Compact models like 8×25 or 10×28 are perfect, even if they sacrifice some low-light performance.
- For Hunting: Consider 8×42 or 10×42. For low-light dawn/dusk hunting, 10×50 provides a brighter image.
- For Astronomy: Go for high light gathering: 10×50 or larger. A tripod adapter is essential for magnifications above 10x.
- For Concerts or Theater: Low-power compacts like 4×30 or 6×30 are often sufficient and less intrusive.
FAQ: Your Questions Answered
What does 10×50 mean on binoculars?
It means the binoculars have 10x magnification, making objects appear ten times closer. The 50 means the front objective lenses are 50mm in diameter, allowing alot of light in for a bright image, ideal for low-light conditions.
Are 10×42 binoculars better than 8×42?
Not necessarily “better,” but different. 10×42 gives you more detail at longer distances but with a narrower field of view and more noticeable hand shake. 8×42 offers a wider, steadier view, which many prefer for general use. It depends on your needs.
What is the best all-around binocular size?
The 8×42 configuration is widely considered the best all-around size. It provides a great mix of magnification, light gathering, field of view, and portability for most outdoor activities.
Which is more important, magnification or lens size?
They work together. Magnification brings you closer, and lens size determines image brightness. For most people, choosing a balanced pair (like 8×42) is more effective than maximizing one spec. Consider where you’ll use them most often.
Can I use high-magnification binoculars without a tripod?
You can, but it’s challenging. For binoculars with 12x magnification or higher, a tripod is strongly recommended to stabilize the image. Even 10x models benefit from bracing your arms or leaning against something for a clear view.
What do the numbers on binoculars case mean?
The case is usually labeled with the binocular model it fits. The numbers on it typically match the binoculars magnification and objective lens size (e.g., 8×42) to ensure you grab the right case for your gear.
Understanding what the numbers on binoculars mean takes the confusion out of shopping. You can now confidently match the specs to your favorite activities. Remember, the best binoculars for you are the ones you’ll actually carry and use. So, consider weight and comfort alongside those important numbers, and you’ll be ready for your next adventure.