eyepiece field stop

A (usually fixed) field diaphragm that's typically located inside of the eyepiece and in a conjugate field plane - in this case the same plane as the intermediate image plane. It sets the final constraint on the observable field of view.

Synonyms: eyepiece field diaphragm

Related MicroscopyU Article

Viewing and Projection Eyepieces

The eyepiece (or ocular) is designed to project either a real or virtual image, depending upon the relationship between the intermediate image plane and the internal eyepiece field diaphragm. Explore how eyepieces can be coupled to the human eye or a camera system to produce images generated by the microscope objective.