Size of Field Microscope

Size of Field Microscope

Quite a general but errorneous idea prevails that the size of the tube has an influence on the size of the field. Except in eye-pieces of very low power, or with tubes with smaller than usual dimensions, this is not so. It must be remembered that a Huyghenian eye-piece admits of a definite size of field, and this is regulated by the opening in the diaphragm ; the same size of opening is used in all of the same power, whether it is an eye-piece for a large or small diameter.

A misconception also exists as to the definition of field. Such inquiries are often made as : " As we understand it, a wide-angle objective gives a larger field ? " but it does nothing of the kind. The angular aperture has no bearing whatever on the size of the field, The field of view, or that which is shown of the object's surface, is determined by the power of the objective and eye-piece.

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