| Fulfilling your bird watching and wild bird | | | | pupil, the brighter the image obtained will be. |
| identification efforts will be realized by | | | | Having a large exit pupil is advantageous under |
| understanding basic binoculars' terminology. | | | | low light conditions and at night such as |
| Binoculars Terminology | | | | astronomical, marine or low light conditions. |
| Power/Magnification and Objective Lens Diameter | | | | Relative Brightness |
| (example 8x42) | | | | Gathering and transmitting enough of the available |
| The first number, the Power or Magnification | | | | light to provide a sufficiently bright and sharp |
| measurement, is the degree that the object being | | | | image define the brightness of a pair of binoculars. |
| viewed is enlarged. In this example, binoculars with | | | | Brightness is certainly one factor to consider |
| an 8 power magnification will magnify the object | | | | when determining the best pair of binoculars for |
| 8 times larger than would normally be seen with | | | | you, but is not usually the most important. After |
| your eyes. The second number, the Objective | | | | all, most of your bird watching likely will be during |
| Lens Diameter, is measured in millimeters (mm). | | | | well lit conditions when birds are active. |
| The objective lenses are the front lenses of the | | | | Eye Relief |
| binoculars. The diameter of the lens determines | | | | Eye Relief is the distance, measured in millimeters |
| the light gathering ability. A larger lens produces | | | | (mm), that binoculars can be held from the eye |
| greater light gathering ability and therefore | | | | and the full field of view can still be observed |
| improved detail and image clarity. The power level | | | | comfortably. Those who wear eyeglass in |
| affects the brightness of an image. A lower | | | | particular benefit from longer eye relief. Normally |
| power will produce a brighter image. | | | | a minimum rating of 15mm will be needed for |
| Field of View | | | | those wearing eyeglasses. |
| The size of the area visible while looking through a | | | | Best Binoculars for Birding |
| pair of binoculars is referred to as the Field of | | | | While the ultimate choice is one of personal |
| View. Generally a greater magnification or power | | | | preference, generally full size binoculars ranging |
| will produce a smaller field of view. The angular | | | | anywhere from 7x30 to 8.5x50 are preferred and |
| field of view, expressed in degrees, is indicated on | | | | considered the most popular range in magnification |
| the outside of the binoculars. The linear field of | | | | and objective lens size for bird watching. For |
| view refers to the area that can be viewed at | | | | instance, binoculars with an 8x42 configuration |
| 1,000 yards, and is expressed in feet. A larger | | | | feature a 42mm objective lens size which |
| field of view translates to a larger area seen | | | | provides ample light gathering capabilities in even |
| through the binoculars. Depending on your bird | | | | lower light conditions and an 8x magnification |
| watching needs, a significantly larger linear field of | | | | allows you to steady the binoculars much more |
| view may not be important. Please remember, in | | | | readily than with significantly higher powers, |
| most cases, the larger the field of view, the | | | | making the task of bird identification easier. Some |
| poorer the image clarity becomes, especially | | | | birders with steady hands may prefer 10 power |
| around the edges. Bear this in mind when making | | | | binoculars or greater. |
| your choice. Bigger does not always mean better. | | | | Please remember that as you increase the power |
| Close Focus | | | | of your binoculars, less light will be gathered and |
| Close focus refers to the distance between you | | | | therefore the viewing field will be reduced as well. |
| and the nearest object on which you can focus | | | | It is also very difficult to keep an image steady |
| while still maintaining a good image and sharp | | | | at very high magnifications using standard hand |
| focus. This term is normally applied only to center | | | | held binoculars. A tripod is often necessary to |
| focus models which may need to focus both near | | | | steady an image at higher magnifications. A good |
| and farther distances. Close Focus distance is a | | | | alternative though for those seeking the option of |
| critical issue with bird watchers and observers of | | | | high power magnification is a pair of binoculars |
| close subjects that tend to move around at | | | | with a zoom feature. This gives you the option of |
| varying distances quickly. | | | | higher magnifications without the limitations of |
| Exit Pupil | | | | fixed, high power binoculars that can be a bit |
| The diameter that of the beam of light, measured | | | | unwieldy. |
| in millimeters (mm), leaves the eyepiece of a pair | | | | Support Staff - the Outdoor Nature Optics from |
| of binoculars is the Exit Pupil. The larger the exit | | | | theOutdoor Nature Resource. |