Depth of Field of Binoculars
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 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 or telescopes 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.
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