Binoculars are classed according to magnification and aperture. A size of 7 x 50, the most suitable size for general observation, indicates a magnifying power of 7 times and an object glass diameter of 50 mm. The exit pupil is the bright disc of light emitted by the eyepiece, a measurement obtained by dividing the aperture by the magnification. For best results, the size of the exit pupil should match that of a fully dilated human pupil (about 7 mm).
| Type |
Magnification |
Aperture (mm) |
Exit pupil (mm) |
| 6 x 30 |
6 |
30 |
5 |
| 7 x 35 |
7 |
35 |
5 |
| 7 x 50 |
7 |
50 |
7 |
| 10 x 50 |
10 |
50 |
5 |
| 10 x 70 |
10 |
70 |
7 |
| 11 x 80 |
11 |
80 |
7.5 |
| 20 x 80 |
20 |
80 |
4 |
What features do binoculars for hunting need?
Any hunter who has spent much time in a deer stand, climbing the western mountain ranges searching for elk, or even calling turkeys in a hardwood forest is aware that using binoculars greatly enhances the chances of success and increases the pleasure of the overall outdoor experience. When properly used binoculars will open your eyes to animals and scenery that may have otherwise been unnoticed. A good pair of binoculars can be a lifetime purchase, and will provide you years of enjoyment and pleasure in observing the great outdoors or the night sky.
Compact Binoculars
Most hunters and bird watchers will be best served by purchasing full- or mid-size binoculars rather than the small compact binoculars that use 20-25 mm objective lenses. Owning a small compact binocular can be very beneficial but it should not be your primary hunting binocular.
Zoom Binoculars
Most hunters will want to stay away from the zoom type binoculars. Although the idea of quickly zooming from near focus to infinity is appealing, in real life this doesn't work all that well. Most zoom binoculars are almost impossible to hold steady at higher magnifications. These binoculars are somewhat fragile and have extremely narrow fields of view.
How much magnification do I need?
You will want a binocular with magnification appropriate to how you plan to use your binoculars. The demands of your hobby should be the most important factor before you select a pair of binoculars. How much detail do you need to see? Will you use your binoculars to view things close up or far away? Will you be able to prop your arms on something for support while using your binoculars? Do I want a small binocular that I can take anywhere?
The most popular binoculars are those with lower magnifications (as with 8x binoculars). These binoculars have wider fields of view and are easier to hold steady than the binoculars with higher magnifications. A wider field of view is important when trying to follow fast-moving action like game on the move, warblers on the wing, or athletes at a fast-pace sporting event.
Higher magnifications (as with 10x binoculars) will give you more detail, but are more difficult to hold steady than binoculars with lower magnification. Binoculars with higher magnification also have narrower fields of view. While many people choose to use 10x binoculars, they are deciding that image size and detail is of greater importance to them.
Note: The diameter of the objective lens is directly related to the size of the binocular -- the larger the objective lens, the larger and relatively brighter the binocular.
What is the field of view in a binocular?
When you look through your binoculars, the widest dimension you can see is known as the field of view. Some binoculars feature unique lenses to provide a "wide field" that is greater than normally seen through binoculars of the same magnification.
A wide-field binocular is desirable for observing at close quarters in deep woods or picking up anything that is moving quickly across your viewing area.
Note: The field of view decreases as magnification increases, so select a binocular with lower magnification if a wide field of view is important to you.
How do I clean my binoculars?
Use common sense in the care and maintenance of your binoculars. Always attempt to blow off any visible dust or dirt from the binocular lenses before brushing or rubbing anything on the glass of your binocular. Next, use a lens cleaning tool like a Lens Pen or lens cleaning tissue to gently wipe off any remaining marks or spots from the lens of the binocular.
Remove stubborn things like dried water spots from the lens of a binocular by lightly fogging the binocular lens with your breath. If your waterproof binoculars are badly soiled, you can even clean them by placing them under lightly running water (to minimize any possible damage).
Note: Don’t use your shirt tail or pocket tissue to clean your binoculars. These fibers may contain material which will scratch the coatings on the binocular lenses.
Keep binocular eyecups and focus mechanisms free of dirt and oil. An occasional wipe with a vinyl or rubber preservative like ArmorAll will extend the life of rubber eyecups on the binocular. Check your neckstrap and its attachments for wear or slippage, too. You don't want your bino to come flying off and hit the ground!
How much should I spend on binoculars?
Buy the best quality binoculars you can afford. This will allow you to spend the greatest possible time with your binoculars pressed to your eyes. You’ve probably heard the old statement about fishing that says “to catch fish, you need to have your line in the water”. Well, you won't see more detail unless that binocular is at your eyes. Poor quality binoculars usually spend a lot of time just dangling from the neck.
Note: Poor quality binoculars also lead to eyestrain, headaches, and are not very fun to use for any length of time. In the long run, you'll probably save money if you initially buy better quality binoculars and avoid trading up later. In the meantime, you'll see so much more--so much better!