Binoculars Explained : Magnification
| Magnification | Aperture | Field of View | Depth of Field | |
| Size & Weight | Eye Relief | Transmittance | Exit Pupil | |
| Optical Design | Focusing | Twilight Factor | Phase Correction | |
| ED (Extra Low Dispersion Glass) |
Binoculars are specified by a set
of numbers such as 7×35 or 8×40 etc. The first number
indicates the power of magnification or how much larger, or closer,
the object will appear than when seen with normal vision. Generally,
the range in magnification for hand-held binoculars is from 6 to
10 in power. In a binocular designation 7 x 35, for example, objects
will appear 7 times larger, or closer, than when seen with the naked
eye.
When considering magnification, more is not necessarily better. As magnification increases, brightness and clarity may diminish, depth of field can become shallower and the field of view is usually more restricted. More noticeable and disturbing at higher powers are fine hand tremors and the effects of atmospheric conditions, such as the distortion caused by heat waves.
If your observation is done primarily at close range, such as in woodland areas or in your backyard, then a good 8 power binocular (such as the Hawke Platinum) might be the best choice. This range of magnification generally gives you a larger picture (wider field of view) which is especially important for viewing objects relatively close at hand.
When considering magnification, more is not necessarily better. As magnification increases, brightness and clarity may diminish, depth of field can become shallower and the field of view is usually more restricted. More noticeable and disturbing at higher powers are fine hand tremors and the effects of atmospheric conditions, such as the distortion caused by heat waves.
If your observation is done primarily at close range, such as in woodland areas or in your backyard, then a good 8 power binocular (such as the Hawke Platinum) might be the best choice. This range of magnification generally gives you a larger picture (wider field of view) which is especially important for viewing objects relatively close at hand.
Also, binoculars of this
magnification usually deliver better performance under conditions
of low available light, due either to the time of day, weather conditions,
or shadows caused by dense vegetation or other structures. This
same type of binocular also works well for fast-moving action like
sporting events, since the wide field of view allows the action
to remain in the viewing area.
For long distance viewing or where greater detail is required, a higher magnification of 10 or over should be considered. For example, the demands of observing in wide open terrain with little cover are best met with a binocular of 10 power or over. This generally holds true for situations where there is a need for critical field mark identification, as in observing raptors and shorebirds or when the object or animal is difficult to approach.
Remember: magnification should only be considered in relation to other factors such as aperture size, exit pupil, hand-held stability, atmospheric conditions, available light, optical design and the weight of the binocular.
For long distance viewing or where greater detail is required, a higher magnification of 10 or over should be considered. For example, the demands of observing in wide open terrain with little cover are best met with a binocular of 10 power or over. This generally holds true for situations where there is a need for critical field mark identification, as in observing raptors and shorebirds or when the object or animal is difficult to approach.
Remember: magnification should only be considered in relation to other factors such as aperture size, exit pupil, hand-held stability, atmospheric conditions, available light, optical design and the weight of the binocular.
