Binoculars Explained : Focusing
| 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) |
There are two basic types of focus
systems on binoculars: centre and individual focusing. Centre focusing
is the most common and convenient and generally the most preferred
as both eyepieces can be focused simultaneously.
All Hawke models are centre focus. On centre focus models, a separate dioptre adjustment on one eyepiece (usually the right one) allows compensation for the differences in the strength of each eye.
All Hawke models are centre focus. On centre focus models, a separate dioptre adjustment on one eyepiece (usually the right one) allows compensation for the differences in the strength of each eye.
Close Focus
The ability of a binocular to focus closely is a much desired characteristic for many situations such as critical identification of birds in the field or observing the intricate detail of insects or plants, for example. The close focus distance of a particular model depends on its optical design and to some extent, on the individuals own eye characteristics. A minimum distance of 6 metres is usually acceptable but many birders prefer models that are capable of a near focus of 3 metres.
The ability of a binocular to focus closely is a much desired characteristic for many situations such as critical identification of birds in the field or observing the intricate detail of insects or plants, for example. The close focus distance of a particular model depends on its optical design and to some extent, on the individuals own eye characteristics. A minimum distance of 6 metres is usually acceptable but many birders prefer models that are capable of a near focus of 3 metres.