If you’ve ever shopped for binoculars or spotting scopes, you’ve seen the numbers. They look like a secret code. Understanding what do the numbers mean on binoculars and spotting scopes is the first step to choosing the right gear. This guide will break it down in simple terms, so you can pick the perfect pair for birding, hunting, sports, or astronomy.
What Do The Numbers Mean On Binoculars And Spotting Scopes
The numbers on your optics are the key specifications. They tell you about magnification and the size of the front lens. For binoculars, you’ll see two numbers, like 8×42 or 10×50. For spotting scopes, it’s often three numbers, like 20-60×85. Let’s decode them.
The First Number: Magnification Power
The number before the “x” is the magnification. It tells you how many times closer an object will appear. An 8x binocular makes something look eight times closer than it does with your naked eye. A 10x makes it look ten times closer.
- Higher magnification (like 12x or 15x) brings distant subjects closer.
- Lower magnification (like 7x or 8x) offers a wider field of view and a steadier image.
Remember, higher power isn’t always better. It amplifies hand shake, making the image shakier without a tripod.
The Second Number: Objective Lens Diameter
The number after the “x” is the diameter of the front lens in millimeters. This is the objective lens. It gathers light. A larger number (like 42mm or 50mm) means a bigger lens that collects more light. This results in a brighter, clearer image, especially in low-light conditions like dawn or dusk.
- Smaller lenses (like 25mm) make for compact, lightweight binoculars.
- Larger lenses provide better image quality but add weight and size.
Putting It Together: 8×42 vs. 10×50
An 8×42 binocular has 8x magnification and 42mm front lenses. It’s a fantastic all-around choice for general use. A 10×50 binocular has stronger magnification and larger lenses. It’s great for long-distance viewing but will be heavier. You need to consider the trade-offs.
Spotting Scope Numbers: The Third Element
Spotting scopes often have a third number because they offer variable zoom. A scope labeled 20-60×85 means:
- 20-60x: The zoom range. You can adjust magnification from 20 times up to 60 times.
- 85: The objective lens diameter in millimeters. An 85mm lens gathers a lot of light for detailed viewing at high power.
This flexibility is why spotting scopes are prefered for serious birding, long-range hunting observation, or digiscoping.
Other Important Numbers and Specs
The main numbers are crucial, but other specifications matter too. You’ll find these on the box or in the manual.
Field of View
This is the width of the area you can see through your optics, usually measured in feet at 1000 yards. A wider field of view makes it easier to follow moving subjects, like birds in flight. Generally, lower magnification gives 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 should roughly match the size of your eye’s pupil in low light (about 2-3mm in daylight, up to 7mm in darkness). A larger exit pupil (over 4mm) means a brighter image that’s easier to align with your eye.
Eye Relief
This is the distance from the eyepiece lens to your eye where you can still see the full image. It’s critical for eyeglass wearers. You typically need 15mm or more of eye relief to see the whole picture comfortably with glasses on. Don’t overlook this spec if you wear spectacles.
Close Focus
This is the minimum distance at which the binoculars or scope can focus. If you enjoy butterfly watching or looking at fine details on close objects, a short close focus (like 6 feet or less) is a valuable feature.
How to Choose the Right Numbers for You
Now that you know what the numbers mean, how do you pick? It depends entirely on your primary activity.
- General Use & Birding: 8×42 is the gold standard. It offers a great balance of light gathering, field of view, and a steady image.
- Low Light & Wildlife: 10×50 or even 8×56. The larger objective lenses maximize brightness at dawn or in forests.
- Long Distance (Hunting, Astronomy): 10×42, 12×50, or a spotting scope (e.g., 20-60×80). Higher magnification is key, but a tripod becomes essential.
- Travel & Hiking: Compact models like 8×25 or 10×28. They sacrifice some image brightness for portability.
- Sports Events: 7×35 or 8×32. A wide field of view is crucial for following the action, and you rarely need high power.
Always try to test different models before you buy. The feel in your hands and the view through the lenses is personal.
Caring for Your Optics
Once you’ve invested in a good pair, take care of them. Keep the lens caps on when not in use. Use a soft brush or air blower to remove dust before wiping lenses with a microfiber cloth. Store them in a dry place to prevent fungus growth inside the lenses. And avoid touching the glass surfaces with your fingers.
FAQ Section
What does 10×50 mean on binoculars?
It means 10x magnification and 50mm diameter objective lenses. It’s a configuration known for good light gathering, suitable for lower light conditions.
Is 10×42 better than 8×42?
It depends. 10×42 brings subjects closer but has a narrower field of view and shows more hand shake. 8×42 is steadier with a wider view. For most all-around use, many prefer 8×42.
What is a good magnification for a spotting scope?
A variable zoom like 20-60x is ideal. You can start at lower power (20x) to find your subject and zoom in (up to 60x) for fine detail. The large objective lens (e.g., 80mm) supports the high magnification with a bright image.
Are bigger binocular lenses always better?
Not always. Bigger lenses (like 50mm) give a brighter image but make the binoculars heavier and bulkier. For daytime use, a 32mm or 42mm lens is often perfectly sufficient and easier to carry.
What does field of view mean?
It’s the width of the scene you see through your optics. It’s like the difference between looking through a window or a tube. A wider field of view makes it easier to locate and track objects.
Choosing the right optics doesn’t have to be confusing. Now that you know what do the numbers mean on binoculars and spotting scopes, you can match the specifications to your needs. Focus on how you’ll use them most, and you’ll find a tool that brings the world wonderfully closer for years to come.