How do ocular microscope objectives work?

[L2obin]

Not sure if this is the right forum, but here it goes.

I would like to understand ow is it that one can see the entire field of view (or close to it) with an ocular objective that magnifies the incoming image say 10X ?

My reasoning makes me think that only a portion of the incoming image would be displayed but this does not seem to be true??

[revi]

very short: the ocular functions as a loupe to observe the image projected by the objective

[ajohnw]

Microscopes have what are called field sizes. The objectives are designed to project an image of a certain diameter and the image quality falls off above that. Eyepieces are also designed to cover a certain field size and in some cases might limit the size of the field of view. Where eyepieces fully covers the maximum possible amount of the tube size that it sits in they are usually referred to as wide field. For ordinary microscopes that's normally a bit short of 20mm where as an ordinary eyepiece might cover 16mm. When projection eyepieces are used for photography they are often limited to a smaller size than the wide field eyepieces.

John
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