Optical Position of Diaphragms using Lens

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“The intersection of the principal rays in this case lies in the middle of the entrance pupil or of the exit pupil. By head and eye motion the various parts of the whole field can be viewed one after another.” —Encyclopaedia Britannica, 1910


Encyclopaedia Britannica (11th ed., vol. 18) (New York, NY: The Encyclopaedia Britannica Company, 1910)


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