Binoculars Explained : Depth of Field
| Magnification | Aperture | Field of View | Depth of Field | |
| Size & Weight | Eye Relief | Transmittance | Exit Pupil | |
| Optical Design | Focusing | Twilight Factor | Phase Correction |
This parameter refers to the distance
from "near to far" that is in focus at a certain setting
of the focus adjustment or at a certain distance. In a given optical
system, as the magnification increases, depth of field decreases.
This fact is one of the disadvantages of observing with high magnifications
and why depth of field is usually more important in comparing spotting
scopes than binoculars.
At very high magnifications, the depth of
field can be so shallow that precise focusing is critical and so
the location, size, action and feel of the focusing adjustment is
an important consideration. Depth of field also changes with the
distance observed, usually decreasing in depth as the distance decreases.