Attracting Birds by Seasons
Mar 6, 2020

Choosing the Right Optics


Choosing the Right Optics
Much like people, with binoculars it’s what’s on the inside that counts. These simple steps will help you find top-notch birdwatching and wildlife binoculars – without paying an arm and a leg.

How Will You Use Binoculars?

Doing backyard birding? Taking a trip to Belize? Hitting the trails and flyways around our region on a regular basis? Using them to nature watch while backpacking? Hunting? Determining the need will help you determine which is the right pair for you.

Know What the Numbers Mean (It's Simple)

Every pair of bins come with two numbers such as 6x32, 8x33, 8x42, 10x42.
Let’s use 8x42. The first number (8x) is always the magnification. For this pair of bins, objects will appear 8 times closer than with your naked eye. That’s it!
The second number is always the diameter of the objective lenses in millimeters (the two big lenses on the front of the bins furthest away from your eyes.) The bigger the objective lens, the more light it lets in So, the bigger the objective lens, the brighter the image will appear, especially in low light conditions such as dawn, dusk and cloudy days.
What 8x42 Means

Trade Off - Magnification

Well, then if 8x is good for viewing birds, 12x must be spectacular, right? Nope! Spoiler alert: birds move a lot! If the magnification is too powerful, you won’t be able to track birds in the air, ground or water. That’s because super powerful magnification cuts down on your field of view. Most birders opt for 8x magnification. It’s a good balance between magnification and field of view. If you want more power, go 10x...tops!

Trade Off - Objective Lens

But the bigger the objective lens, the larger and weightier your bins will be. Most birders who get out in the field on a regular basis opt for a 42mm objective lens. It’s a great balance between size and clarity. Smaller travel pairs with 32mm objective lenses do a great job, too.
Huge Objective Lens = Huge Binoculars
42mm = Comfortably-Sized Binoculars

Porro vs Roof Prism

Porro prism bins have the classic shape that’s been around forever. Roof prism bins are more streamlined. So, which one is better? They’re both the same optically. Cross my heart. Roof prism bins just tend to be narrower, less bulky and a bit easier to hold and store. That’s it!
Roof Prism Binoculars
PorroPrism Binoculars

Fully-Multi Coated Lenses (Inside and Out)

You really want this! It means EVERY lens you can see on the bins (and many inside that you can’t) are coated front and back with anti-reflective material. Consider this: each uncoated lens in a bin can reflect up to 5% of light. Bins can have 15 lenses or more. That means a whole lot of light isn’t making it to your eyes. Which is why images viewed through cheap bins look dim or muddy even on bright days.

Waterproof Means Nitrogen Filled

Simply being sealed against water isn’t enough for bins to be truly waterproof. That’s because oxygen is still trapped inside. And air contains moisture. So, take supposedly “waterproof” bins from a hot car into cold air (or vice versa) and they’ll fog up like the Scottish Highlands. Make sure your bins are “waterproof nitrogen filled.” That means they’re filled with nitrogen before they’re sealed. And since nitrogen can’t contain moisture, they’ll never fog on you.


This is the #1 thing that can spoil your viewing experience, even with the best pair of bins. The two lenses you look through have eye cups around them. They rotate out and in. Keep them IN if you don’t wear glasses. Rotate them OUT if you do. This will ensure the eye relief (proper distance of eye to lens) is correct. If you don’t, you’ll see incomplete half-moon images of what you’re viewing (and probably think your bins suck!)
Twist the eye cups out if you DON’T wear glasses. If you DO wear glasses, leave them in.


Some bins from Germany and Austria can START at $1,500! Yet optical technology advancements have made great bins far more affordable for everyone to enjoy. BWS carries Opticron – a UK brand that’s the #2 seller in Europe. After much research, we chose this 50-year-old brand because it provides truly spectacular clarity and quality (with a lifetime guarantee) at an equally spectacular price. (You can get top-notch Opticron binoculars and still save about $1,150 or more over what the Austrians are offering.)

Sighting Bins In

Everybody’s eyes are different. So, picking up a pair of bins not corrected to your eyes is like looking through someone else’s glasses and expecting to see clearly. So, always sight in your bins even when you’re trying them out. Here’s how:
Every pair of bins have two focus controls: 1. a middle knob between the two barrels of the bins that focus both eyes and 2. A ring around the right eye piece that ONLY FOCUSES THE RIGHT EYE.
  1. Pick an object approx. 20 yards away.
  2. Twist to extend the eye cups if you DON’T wear glasses. If you DO wear glasses, don’t extend them.
  3. Using your bins, close your right eye and look at the object you’ve chosen through your left only.
  5. Now, close your left eye and look at the object through the bins using your right eye only.
  7. Open both eyes and look at the object through your bins. It should be clear.
  8. Use the center focus knob here on out to focus on all objects you wish to view.