The Ultimate Guide to Choosing Bird Watching Binoculars!
I was a bit overwhelmed at all the features and technical specifications, especially for someone who still considers themselves a beginner. I found myself taking lots of notes, creating spreadsheets and talking to as many dealers and companies as possible, I started to get paralysis by analysis!
That is how this guide was born! I wanted a resource that explains the differences (especially in price) between different binoculars and educate about the features most important to us birders.
Binoculars are made for all sorts of purposes (hunting, astronomy, the opera, sports games, etc) and have all different sizes, shapes and specifications. I found there is a sweet spot when it comes to finding a great binocular that fits the needs of a birder.
- ***The Best Binoculars for Bird Watching.***
- Related link: I narrowed down a list of my favorite binoculars across all prices ranges that fit the needs of birders.
Table of Contents:
The 6 Most Important Specifications and Features For Bird Watching:
- Objective Lens Diameter
- Field of View
- Close Focus
- Roof vs Porro Prisms
- Waterproof and Nitrogen Purged
The Features That Affect Price:
Typically the more you spend the better the image, which is effected by the following following.
Other Important Things to Consider:
The 6 Most Important Specifications and Features:
1. Magnification: The First Number
2. Objective Lens Diameter: The Second Number
3. Field of View (FOV): The visible area seen through your binoculars.
- Angle of View: Some manufacturers will give the Angle of View instead of the Field of View. They represent the same thing, but you will need to convert the Angle of View to Field of View.
- To do this, just multiply the angle by 52.5. For example, if the Angle of View is 8 degrees, the FOV would be 420 feet. (8 x 52.5 = 420)
4. Close Focus:
5. Roof vs Porro Prisms:
The prisms in your binocular come in two different styles. The difference is how light enters and travels through the binocular and prisms.
Porro Prism: Light zig zags through the binocular.
Porro Prisms: When light enters the lens, it does a zig zag through the binocular to get to your eye. Porro prism binoculars were standard until companies like Zeiss introduced Roof prism binoculars.
- The biggest advantage of a Porro prism is that they are cheaper to manufacture. This means you can get a higher quality binocular for the same price range of a Roof prism.
- The disadvantage is that Porro style binoculars are much heavier, clunky and difficult to carry around!!
Roof Prisms: Though they are smaller, compact and more streamlined, these prisms are more complicated internally. Light goes straight through the barrel to your eye.
- Highly Recommended: Most bird watching binoculars will be a roof prism design. They are so much easier to carry around and use. They fit in your hand much better and weigh less.
- The main disadvantage is that for the same quality binocular, they will cost a bit more than a porro prism. This difference very worth it!! To be honest, the prices don’t vary much anymore. Most companies have focused extensively on designing roof prism designs because they are so much easier to carry and preferred by customers.
6. Waterproof and Fog proof:
- Waterproof: Most companies use this term to mean that water can not enter. Usually, they will indicate how far underwater or how long underwater they can go before there could be a problem. Make sure it’s Waterproof and not just weatherproof.
- Fog proof: To prevent your lenses from fogging up in moist or humid conditions, your binocular will need to be filled with dry nitrogen (or argon) gas instead of oxygen. Many times the description will say “nitrogen purged” or “nitrogen filled”.
The Features That Affect Price:
I am going to give a quick quiz!
Looking at the binocular models below, try and guess the approximate cost, or at least try and guess which one is most expensive.
I am only listing the specifications discussed from the above section “The Most Important Specifications and Features for Bird Watching.”
So what do you think?
Looking at just this above table, you might believe that the Nikon Monarch would be more expensive than the Leica Ultravid HD-Plus. They have very similar specifications, with the Monarch having a better Field of View and Close Focus.
The 6 specifications and features that are wanted for bird watching don’t necessarily affect the price of the binocular.
So, what does affect the price?
It’s all about the image quality! With few exceptions, the image quality is correlated to the price of the binocular.
My recommendation is to spend as much as you can responsibly afford! Trust me, it’s worth it.
The binocular industry is very competitive and there are many great companies and models on the market. Birding optics can cost anywhere from $100 to upwards of $3,000. Because the industry is so competitive, you are going to get what you pay for.
More $ = Better Image and Picture.
As we have discussed, binocular manufacturers are on a never ending quest to provide us with a perfect image. Some of the common issue’s consumers experience are loss of brightness and color, depth of field issues, chromatic aberration, fringing and crispness. Many of these are compounded in challenging light environments such as in shady woods or sunrise/sunset.
Again, normally the more expensive the binocular, the better image that should be expected.
***Important Note: Most companies don’t reveal much detail when it comes to the below information. These are kept top secret so as not to lose a competitive advantage. For example, Zeiss has been in business a LONG time. They have perfected their engineering and coatings over many years and are not very willing to share their best practices with other companies!***
1. Type and Quality of Glass and Prism:
The importance of the glass and prism can’t be understated! Think about it, light travels through the glass and prisms to reach your eye.
A whole post could be dedicated to the science that happens inside a binocular and how the glass can affect the image. Until that happens, here is a summary:
BK-7 Prisms vs. BaK-4 Prisms:
- BK-7 Prisms are found in very low priced binoculars.
- BaK-4 Prisms are found in most birding binoculars over $100. They have a higher refractive index.
- There is a vast difference in quality among optics that have BaK-4 Prisms. For example, some are manufactured in China, which supposedly has a lower refractive index than true BaK-4 Prisms. The quality and performance varies among different companies and how they engineer their prisms.
Types of Glass in the Lens:
- Standard Glass.
- Extra Low Dispersion (ED) Glass: This is a high quality glass that was only found in the top binoculars, but now is much more common across all price ranges. One of it’s best benefits is it helps reduce chromatic aberration – which is the inability of the lens to focus all the colors to a single point. It causes color fringing around the edges of the image.
- High Definition (HD) Glass: This is a marketing term used interchangeably with ED Glass.
- Flouride (FL) Glass: It is also a type of ED glass but the lens also contains fluoride. So all FL glass is ED glass, but not all ED glass contains fluoride.
- Zeiss has a pretty good explanation of their FL glass.
As light moves through your binocular, it enters and leaves different glass surfaces and lenses. Each time this happens, about 5% of the light is reflected back. This creates a problem when that light is relied upon to make the image bright and clear but only half of it reaches our eye!!
To fix this problem, companies have developed complex coatings as thin as a few millionths of an inch that is applied to the glass. Every company has their own different coatings and there is no industry standard, but here are a few terms to keep in mind.
- Coated: At least one coating on the lens surface. Normally magnesium fluorite is used. Cheap binoculars!
- Fully Coated: At least one coating on all air-to-glass surfaces.
- Multi-Coated: Has multiple coatings on at least one of the lens surfaces.
- Fully Multi-Coated: All lenses and internal air-to-glass surfaces are multi-coated. This costs the most to manufacture, but will let the most amount of light through to your eye.
Dielectric high-reflective multi-layer prism coating: I thought it was important to mention this type of coating specifically, because it’s found on Roof style binoculars on the prism and is a great coating to have. It can achieve light reflectance that exceeds 99%, which means better and brighter images! Normally this coating is found on higher end binoculars.
Phase Correction Coating: This coating is also found on better binoculars and is only needed for roof style optics. A roof surface can cause a phase shift of light, which affects the image. The phase correction coatings helps to minimize this occurrence and keep the image clear.
The way a binocular is engineered and designed is going to trump many of the other features mentioned in this section.
For example, a binocular can have the best ED glass available, be fully multi-coated on all lenses and have a dielectric high-reflective multi-layer prism coating and still have a really bad image when it reaches your eye!! These features are very important, but useless if the company that made the binocular did a poor job of putting everything together.
Before making a purchase, I recommend doing some research on the manufacturer and learning their reputation.
Other Important Things to Consider:
So far we have covered two things. First, the most important binocular specifications needed for birding. Second, some of the technology that affects the vast price differences you see among binoculars.
In this section is a list of other questions to ask yourself and to consider. Buying binoculars is a highly personal choice and there is no “one size fits all” model.
While shopping, consider the following!
Ease of Focus:
- There is nothing more frustrating when a bird lands a few feet in front of me and I can’t focus my binoculars fast enough before it flies away!! Every optic focuses a bit different, so it’s important to consider.
- Make sure the binocular you choose only has one central focusing knob and it should be positioned comfortably under your index finger.
- Is it easy and smooth to focus or difficult and stiff? Can you get a fine focus quickly? Remember, you don’t want to miss any action while messing with the focus.
- It is the distance that a binocular eyepiece can be held away from your eye and still see the whole Field of View.
- Very important to consider if you wear eye glasses since you already start a little farther back from the eyepiece.
- In my opinion, a warranty is a reflection of how confident the manufacturer is of their product. Do they have faith in their engineering? Will it hold up to the rigors and stresses of birding?
- Every company has a different warranty, so it’s very important to consider. Also, some warranties are voided if the product isn’t registered or if proof of purchase can’t be provided.
- Lifetime Warranty for manufacturer defects. Many companies offer this outstanding benefit. (e.g. Zeiss, Leica, Nikon)
- Many also provide a warranty for a limited time for accidental damage that is your fault. For example, Zeiss includes a 5 Year No Fault Policy. This covers any damage caused by normal and intended use!
Weight and Feel:
Before making a final decision on a binocular, it is very helpful to hold it in your hand and be able to test it in the field.
- How much does it weigh? Is this too heavy to carry around all day?
- Does it fit well in my hands? Can my fingers access the focus easily?
***Recommended: Under 30 ounces (about 1.9 lbs).
- Remember from above, as the Objective Lens Diameter increases, so does the size and weight of the binocular. This is one reason that 42mm is recommended for the diameter size. It’s my preference for the best combination of image quality and brightness and the weight is still comfortable.
- If weight is a concern, my recommendation is to buy a more “mid sized” binocular. Basically, look for an Objective Lens Diameter between 30-35mm. The weight and size tends to be smaller and not a lot is sacrificed on the picture quality.
My recommendation for a bird watching binocular has the following features and benefits:
- Spend as much as you can reasonably afford to ensure the best image possible. Minimum for a decent birding bin is $125, while the most expensive will cost close to $2,500. There are plenty of options in between.
- Magnification: 8x
- Objective Lens Diameter: 42mm
- Close Focus: under 6.5 feet or 2 meters.
- Field of View: Above 380 feet.
- Roof style.
- Waterproof and Fog proof.
- Easy to focus.
- Great warranty.
- Light enough to carry in the field all day and feels good in your hands.
And there you have it!
Check out my page on the Best Bird Watching Binoculars. I narrowed down some of my favorites across many price ranges and wrote a review of each.
Lastly, let me know what you think of this guide below.