| 摘要 |
In a single lens reflex camera, a mirror can be positioned in an upright light-reflecting position between the rear of the taking lens and the film to reflect the light rays that come through the lens on to a focusing screen of the viewfinder, and it can be positioned in an inverted non-reflecting position out of the way of the light rays to allow them to expose the film. The mirror is supported to pivot about two axes, forward toward the rear of the lens and downward to at least partially underneath the film, from its light-reflecting position to its non-reflecting position. According to a unique construction, the mirror is constrained to pivot first only about one of the axes and then only about the other axis to swing successively along respective arcs. This arrangement advantageously allows the back focus of the lens required to clear the mirror for movement from its light-reflecting position to its non-reflecting position to be reduced.
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