Binoculars

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A good pair of binoculars is your most important tool in identifying a variety of birds. If you have never used binoculars for this purpose you will be amazed at the detail and color you will see. A whole new world is about to open up.

There are several characteristics shared by all binoculars that are well suited for bird watching. Your old pair of opera glasses does not have any of them. (Well, they are light weight.) These are some of the key points to consider when selecting a new pair of binoculars.

1. Magnification
Most binoculars will have a series of numbers printed on the body of the binocular, usually just below the eye piece. You will see a number like 7 X 35 or 8 x 42 or 10 x 50.

The first number, the 7 , 8 or 10, is the "power" of the binocular. Objects seen through a 7x binocular will appear 7 times closer than they really are. Objects seen through a 10x binocular will appear 10 times closer than they really are.

Most bird watchers prefer a 7x or 8x binocular. Lower powers do not provide enough magnification and higher powers have a narrow field of view and can be difficult to hold steady.

2. Exit pupil - Light gathering capability
The second number is the diameter of the objective lens, which is the lens on the big end of the binocular. It is a measure of the diameter of the lens in millimeters. Thus a 7 x 35 binocular has an objective lens with a 35 mm. diameter and a magnification of 7 times.

The diameter of the objective lens has an effect on the "light gathering" or image brightness of the binoculars. In general, the larger the diameter, the brighter the image. More specifically, the diameter of the objective lens divided by the magnification provides a good indication of the potential light gathering capability of the binocular. The higher the number the better.

A 7 x 35 binocular is 35 divided by 7 or a 5.0 ratio, which is considered good. Avoid binoculars that have a ratio much below 5, such as a 7 x 30 or 7 x 25.

3. Field of view
Another number that is usually printed on the body of the binocular is the field of view. A large field of view makes it easier to locate a particular bird. You will usually see the field of view measured in terms of viewing angle ( 6 degrees, for example) or 400 feet at 1000 yards. Avoid binoculars that have a field of view under 6 degrees or less that 300 feet.

4. Close focal distance
Another key factor in selecting the right binocular is the shortest distance down to which the binoculars can focus. Some of the less expensive binoculars available in the department and discount stores will only focus down to about 30 feet or more. There will be many occasions when you will want to be able to focus down much lower than this. Some binoculars designed for bird watchers can focus down as close as 5-6 feet.

The close focus distance is not usually marked on the binoculars. You'll have to test them yourself or ask the person from whom you are purchasing the binoculars.

5. Eye glasses relief
The eye relief determines how far your eye can be from the eyepiece while still allowing a full field of view through the binocular. This is important to eyeglass wearers. Look for a High Eye Relief design if you plan to wear glasses while using your binoculars. 15 mm or greater.

6. Design
There are two standard designs utilized in binoculars. The porro prism design has an offset barrel. The roof prism design has a straight barrel. The roof prism design has historically been lighter in weight, slightly smaller and more expensive. Either design, however, is acceptable.

7. Size and Weight
The size and weight of the binoculars can make a difference if you become an avid birder and spend hours in the field. The choice is a personal one, however, and you may need to try several pair to find the ones that you like best.

8. Lens coatings
Many binoculars tout special lens coatings and special types of glass. The special coatings are designed to provide increased brightness and clarity to the image. Some binoculars can cost well over $1000.00 and feature exotic glass and coatings.

Binocular Selection Check List
Feature
Recommendation
Magnification
7x35, 7x42, 8x40 or 8x42
Field of View
Minimum 6 degrees or 300 feet at 1000 yards
Close Focal Distance
20 feet or less
Eye Glass Adapter
Rubber cups or similar device - 15 mm minimum eye relief

A wide selection of quality binoculars is available from the Birdzilla store.


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