Before revision: The exit pupil is an image of the aperture ; divergent rays from each point in the aperture come together again in the exit pupil.|330x330px To use an optical instrument, the entrance pupil of the viewer's eye must be aligned with and be of similar size to the instrument's exit pupil.
After revision: (real or virtual)made by the optics following itplane(focused)The exit pupil is an image of the aperture ; divergent rays from each point in the aperture come together again in the exit pupil.|330x330px To use an optical instrument, the entrance pupil of the viewer's eye must be aligned with and be of similar size to the instrument's exit pupil.