Choosing Binoculars

 

So if your looking for Binoculars this information will help you make an informed decision as to the type of Binocular to purchase. It is ultimately important that before making the investment that you decide on the need. What ever their use they can be very enjoyable. My self I enjoy Bird Watching. 

Whether your search for binoculars is for Bird Watching and Wildlife, Hunting, Sports, Boating or Law Enforcement there are some important things to consider before buying binoculars. Consider what, where and how often you will you will be using them in order to get the right combination of features that are right for your needs.  It’s important to know how binoculars work and their various parts.

 

 

Terminology

1:

Diopter Adjustment

2:

Ocular Lens Assembly

3:

Prism System

4:

Focus System

5:

Hinge

6:

Objective Lens

 

 

First of all you should understand the numbers and what they mean. On the binoculars are numbers such as 10 X 42, 8 X 42 10 X 50 and so forth. The first number is the magnification which is how large the object is that you are viewing compared to viewing that object without binoculars. With an 8 X 32 binocular, the object being viewed appears to be eight times closer than you would see it with the unaided eye. The benefit of a higher magnification is that you can get a view of things further away although there is a narrower field of view which means you are looking through a smaller window so you see less area. This makes it harder to track the object that you are looking for. The best thing to do is find your object with the naked eye and then find them through your binoculars.

A disadvantage of higher magnification is the shakiness. This is because at higher magnifications even a little shaking in your hands will make the image blur to the point that it may not be usable. As a general rule, if you'll be holding your binoculars you won't want magnification greater than 10 X.  The second number in the formula, (8 X 32) is the diameter of the objective or front lens. The larger the objective lens, the more light that enters the binocular, and the brighter the image.

Objective Lenses of a Binocular

One of the most important and expensive elements in a binocular is the optical coating of the lenses in a binocular. This applies to any optical device, for that matter. As light hits a lens, some of it gets lost in the optic and does not transmit further. To achieve greater light transmission, optics are coated with special chemicals. The goal of any optic is to maximize the amount of light entering the objective lens to the eye.

Binoculars are designated as coated, fully coated, multi-coated, or fully multi-coated. This tells you how many layers of optical coatings are on how many lens surfaces.

Coated Lenses - a single layer on at least one lens surface

Fully Coated Lenses - a single layer on all air-to-glass surfaces

Multi-Coated Lenses - multiple layers on at least one lens surface

Fully Multi-Coated - multiple layers on all air-to-glass surfaces.

With fully multi-coated lenses it is possible to achieve close to 95% light transmission. That means that 95% of all light coming through the objective lens reaches the eye. The image is higher contrast and appears more clearly than with less lens coatings. Better optical quality also delivers better resolution, or the ability to distinguish between fine details and retain clarity.

 One of the numbers you will see in a specification table for binoculars, is an exit pupil. This refers to the size of the circle of light visible at the eyepiece of a binocular, the larger the exit pupil, the brighter the image. To determine the size, divide the objective lens diameter by the power (an 8 X 32  model has an exit pupil of 4 mm).

Exit pupil is a very rough guide to image brightness. Binoculars with large exit pupils provide brighter images under very low light conditions. For normal daylight viewing, an exit pupil of 2.5 or 3 is fine. For astronomy, an exit pupil of 5-7 mm is preferred. An exit pupil larger than 7 is a waste of light.  Since the human eye cannot open wide enough to accept an exit pupil larger than 7.  

 For those that don't always wear eyeglasses, but don't have 20/20 vision or have different vision in both eyes can use diopter adjustment. This is a fine focus adjustment usually provided around one eyepiece to accommodate for vision differences between the right and left eyes. Eye relief is the distance a binocular can be held away from the eye and still present the full field of view. Extended or long eye relief reduces eyestrain and is ideal for eyeglass wearers. Binoculars come with Twist-Up, Pop-Up or soft rubber Fold-Down eye cups which go down for eyeglass wearers. These options allow everyone to see the entire field of view.

 Field of View (FOV) is the diametrical measurement of the circular viewing field or subject area. It is defined by the width in feet or meters of the area visible at 1000 yards or meters. A wide angle binocular features a wide field of view and is better for following action. Field of view is determined by two things. First is magnification. In general, as magnification goes up, field of view goes down. A     10 X will show more detail in that fence at 1000 yards than an 8X, but it will not show you as wide a section of fence. The second thing that determines field of view in a binocular is the eyepiece design. Wide-angle design eyepieces of good optical quality, however, are expensive. Inexpensive binoculars with wide angle eyepieces are usually not as sharp as standard binoculars. Most binoculars have a focus knob and the specifications of the model will list a 'minimum focus' or 'close focus'. This is the nearest distance at which a binocular will focus on an object. A binocular will not focus on an object closer than this distance. This feature is important for some applications such as birding.

 Standard Size Binoculars - A standard or full-size binocular can be used for everything from nature observation to spectator sports.

Compact Binoculars - smaller and lighter in weight and are a good choice to take along to the theater or concerts or on hikes and hunting trips.

Wide Angle Binoculars - ideal for tracking fast-moving action across wide areas such as football fields, racetracks and wilderness terrain.

 PORO and ROOF PRISM BINOCULARS

Binocular come in two different prism systems - Porro and Roof Prism. In Porro prism Binoculars the objective or front lens is offset from the eyepiece. Porro prism binoculars provide greater depth perception and generally offer a wider field of view. In Roof Prism binoculars the prisms overlap closely, allowing the objective lenses to line up directly with the eyepiece. The result is a slim, stream-lined shape in which the lenses and prisms are in a straight line. Most optical prisms are made from borosilicate (BK-7) glass or barium crown (BAK-4) glass. BAK-4 is the higher quality glass yielding brighter images and high edge sharpness.

Porro vs. Roof Prism Binoculars Diagram

 

 

 

 

Zoom Binoculars - A zoom binocular allows the user to increase the magnification in order to focus in on the details. From distant to near view, it's the best of both worlds.

Waterproof Binoculars - waterproof binoculars deliver clarity despite foul weather conditions including fog, rain and ice. O-ring sealed and nitrogen purged for reliable fogproof, waterproof performance.

 Armored Binoculars - a binocular with a housing covered by rubber or other synthetic material. Armoring does not make a binocular a waterproof binocular, but it does protect it from scratches, makes it more comfortable to hold and also "quiets" the binocular when it accidentally bangs against something.

Center focus binocular - This type of a binocular uses a single wheel to focus on objects. It can focus on objects both very close and far away, making it the most versatile and commonly used focusing system in a binocular.

Individual Eyepiece Focus Binoculars - An individual eyepiece focus binocular requires you to focus each eyepiece when looking at an object, but once focused for your eyes, objects from 40 yards away to infinity are always in focus and require no additional focusing. This is a great system for medium range and long range objects, but it is not well suited for close in work. IF binoculars are most commonly found in marine binoculars and astronomy binoculars.

No Focus, or Focus-Free Binoculars - This is an economy version of an individual eyepiece focus binocular, but the eyepieces are locked and set at the factory and cannot be adjusted. This means that you can never focus on objects closer than forty yards away and it also means that the binocular cannot be adjusted for differences in strength between your right eye and left eye. This is a serious shortcoming for most people, since most have one eye a bit stronger than the other.

 General Use Binoculars - Hiking, Stadium Sports, Outdoor

Hunting Binoculars

7 X to 10 X binoculars are best for hunting application. For long range shooting, such as varmint hunting, a 12 X to 16 X magnifications is best. At larger magnification, you will need to use a tripod or to stabilize the binoculars, as the image will be very shaky if used in standing position. The shaking of your hands is amplified by the larger magnification.

Bird Watching

The standard binocular for birding is an 8 X 42 binocular. To see more details on smaller birds at greater distances, you may opt for a 10 X or a 12 X magnification with a 42 or a 50 millimeter objective. Longer eye relief and a close focus are also great features to have on your bird watching binoculars.

Boating and Marine Binoculars

Since you're on the water, a high magnification binocular is not advised. Most commonly used magnification is a 7 X, but 8 X and 10 X are also chosen by some mariners and boating enthusiasts. A 42 or a 50 millimeter objective lens should be used. A larger objective lens, waterproof and rubber armoring are main features to look for in a marine and boating binocular.

Concert/Theater Binoculars

Compact binoculars with a wide angle are great for concert and theater viewing using a binocular. 4 X 30, 5 X 25, 8 X 25 and 7 X 18 or 7 X 21 are great for venues such as opera, theater and music concerts.

 General Use Binoculars

A pair of general use binoculars in the middle of magnification keeps them portable, powerful and capable of great viewing success for all sorts of applications, from birding and wildlife observation to hunting and law enforcement.  

 Compact and wide angle binoculars are great for outdoor activities and getting closer to the action watching sporting events at stadium. Compact binoculars are usually found at 7 X to 10 X magnification ranges. Compact binoculars are easy to store in your pocket or on a strap around your neck and the wide angle presents a good field of view.

Lens Coatings

One of the most important and expensive elements in a binocular is the optical coating of the lenses in a binocular. This applies to any optical device, for that matter. As light hits a lens, some of it gets lost in the optic and does not transmit further. To achieve greater light transmission, optics is coated with special chemicals. The goal of any optic is to maximize the amount of light entering the objective lens to the eye.

Binoculars are designated as coated, fully coated, multi-coated, or fully multi-coated. This tells you how many layers of optical coatings are on how many lens surfaces.

Coated Lenses - a single layer on at least one lens surface

Fully Coated Lenses - a single layer on all air-to-glass surfaces

Multi-Coated Lenses - multiple layers on at least one lens surface

Fully Multi-Coated - multiple layers on all air-to-glass surfaces.

With fully multi-coated lenses it is possible to achieve close to 95% light transmission. That means that 95% of all light coming through the objective lens reaches the eye. The image is higher contrast and appears more clearly than with less lens coatings. Better optical quality also delivers better resolution, or the ability to distinguish between fine details and retain clarity.

I hope this helps you make a more informed decision as to which degree of magnification your need. Many of the binoculars described here can be found at the outdoorfamilystore.com Take a look and if you cant find what your looking for, by all means, contact me and I will make every effort to provide you with what you are looking for.

And as always, Enjoy The Great Outdoors!!!

 

 

 

 

 

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