Depth of field:
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Depth of Field: The area above and below the focal plane in the object (i.e., specimen) which is still perceived as sharply imaged.
The thickness of the optical slice through a specimen that is in focus in the observed image. The depth of field is dependent on geometric and wave optical parameters and varies with the total magnification, the numerical aperture of the objective and the wavelength of the light.
The following formula assumes that the smallest detectable object point can expand to a diameter of up to 2 min/arc before loss of resolution occurs (permissible “circle of confusion”):
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Depth of field
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Depth of focus
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