| 摘要 |
Exposure meter comprises a measuring element (11) which measures the light beam portion leaving the upper section of the exit surface (8) of a pentaprism which forms part of the finder, after this light beam portion has been reflected by the two sloping roof surfaces (5, 6) and the front surfaces (7) of the pentaprism. An optical device (9) comprising a transparent body with a refractive index at least equal to that of the pentaprism has one surface in contact with part of the exit surface, so that the light beam portion, which after reflection by the two roof surfaces, the front surface, and the roof surfaces again, is the object of total reflection by the exit surface portion, leaves the exist surface. The light beam portion is then measured via the optical device by a second measuring element (12). |
