Field of View, or FOV, is the amount of the observed object that can be seen with a particular optics combination. It is the circular area which can be seen when looking into a microscope. It is a combination of objective and eyepiece characteristics; field of view decreases with increasing magnification. In most cases, the field number of the eyepiece can be used to determine the FOV or field size using the following formula:
Field Size = Field Number ÷ Objective Magnification

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