The Basics
About Birding Binoculars

While you should choose the best birding binoculars you can afford, you can begin with a simple, inexpensive pair.  As your bird watching hobby progresses past casual interest you may want to upgrade to better quality.  But no matter whether you are beginning or are a more experienced birder you should have a basic understanding of birding binocuars so you can select those that are best for your style of bird watching.

To help reduce the difficulty and confusion that arises around selecting the right binoculars, you'll find help here.  While watching birds may be the most demanding use of binoculars, the same basic principles, terms and definitions regarding all binoculars apply to those appropriate for bird watching.  The factors determining the best choice among birding binoculars vary with the quality and design of the binocular, as well as the conditions under which they are used, and the preferences of the birder using them.

Why are birders considered the most demanding users of binoculars?  Because they not only must spot birds but must also identify them.  Birding binoculars must deliver good results:

• Birding binoculars must provide very sharp views so fine details can be seen.
• Birding binoculars must perform in all kinds of weather conditions, and at all hours of the day and night.
• Birding binoculars must provide the ability to view an image quickly.
• Birding binoculars must be able to deliver the best view in all conditions.

Note:  My recommendation for the best selection and best prices is  Eagle Optics: The source for binoculars, spotting scopes, tripods and accessories since 1986!  I purchased my binoculars from them and the experience was excellent.  They are the perfect company to do business with and even have a 30-day money-back satisfaction guarantee.  My binoculars are Stokes Birding Series DLS 8x42's (also available in 10x42).  Learn more about my binoculars.

What's With All Those Numbers and Techno-Terms?

There are some factors to consider in choosing the best birding binoculars to fit your preferences and needs.  Here are some descriptions and specifications you should understand before selecting your binoculars ...

Viewing Your Subject

Power

• Objects appear larger with increased power (magnification) providing more ability to see detail like field marks.  Binocular magnification is determined by numbers.  In this example, the first number (8) in 8x42 binoculars make the image 8 times larger to the naked eye.  The second number (42) refers to the diameter in millimeters of each front objective lens.  A larger diameter objective lens gathers more light, provides better detail, a cleaner image and larger field of view.  However, a larger objective lens adds more weight.  How large a lens you need depends on how much magnification you require.
• With increased magnification it becomes more difficult to hold your binoculars steady, you'll have a narrower field of view and less depth of focus, brightness and clarity diminish, and heat wave distortions become more noticeable.  There are tips for holding binoculars steady but there may be some recommended powers (i.e. 10x) that are still too difficult for some people to manage.
• Choosing a lower magnification than 7x or 8x may sound appealing because of their smaller size and lighter weight.  But these smaller binoculars have a small, darker and narrower image making them much less desirable for birding.  The recommended magnification for birding is 7x or 8x.

Field of View

• FOV means the width of the scene that can be viewed at 1,000 yards (or meters).  It is easier to find birds with a wide field of view.  For instances, if you scan the sky for hawks, flocks of shorebirds on the mudflats, or birds in flight you may want to consider binoculars with a wider field of view.  But there are trade-offs.  With a wider FOV you will lose some ability to resolve details.  Also, a too-wide FOV often results in distortion at the edges of your image.  All factors being equal lower magnification means wider field of view.  The recommended minimum field of view is 300 feet at 1,000 yards.

Exit Pupil

• This is the size of an image at the binocular's point of focus.  The exit pupil's ratio should be between 4 and 5 which provides a brighter image.  Interestingly, a 4 to 5 ratio also means it is easier for your eyes to remain on the image when it is bright out and your pupils are contracted.  If the exit pupil is below 4 there won't be enough light gathered to support the amount of magnification so the image will be dark and indistinct.  This is less of a problem on a very bright day.
• An exit pupil is determined by dividing the object lens size by the magnification power.  Using my 8x42 binoculars as an example, you'd divide 8 into 42 with the result of 5.25, a good exit pupil ratio.  Complete details on my binoculars.

Eye Relief

• This is the distance behind the occular lense at which the image is in focus.  In other words, it is the distance between your eyes and the lens you look through when your image is in focus.  Eye relief is especially important to people who wear glasses.  Eyeglass wears can't get their eyes as close to the occular lenses so the full image can't be seen.  Binoculars with eye cups that can be folded down or adjusted by rotating in and out provide sufficient eye relief so the eyeglass wearer can see a full image.  Binoculars with at least 15mm eye relief is considered sufficient.  Long eye relief usually reduces the field of view.
• If you currently wear glasses because you are nearsighted or farsighted you can use your binoculars without your glasses.  The focusing capability of the binoculars will compensate for the removal of your glasses.  However, if your glasses correct for astigmatism you will need to wear your glasses with your binoculars so those offering good eye relief becomes especially important.

Close Focus

• Improvement in optics now give us the opportunity to buy binoculars which can sharply focus on objects at 10 feet or less ... the with champ focusing at 3 feet!  Since all binoculars focus at infinity, consideration should be given to how close you can focus with them.  The need to close focus comes into play more often that you might realize.  It is also important for birders that might also enjoy watching butterflies ... another fast-growing hobby.  Good birding binoculars should be able to focus at 10 feet or less.  Mine focus at 4.5 feet.

Continue to Page 2 ... The Binocular Lenses and more