1. Field of the Invention:
This invention relates to a reflex camera having a half-reflection fixed mirror and other optical elements associated therewith.
2. Description of the Related Art:
Conventionally, as shown in FIG. 16, when in the viewing position, a first optical element 901 (main mirror) for splitting off part of the light passed through the photographic lens (or an object image bearing beam) toward the photographic system, is arranged nearly 45 degrees with respect to an optical axis of the photographic lens and a second optical element 902 (submirror) is arranged nearly 90 degrees with respect to the first optical element 901 to direct the split-off beam for the photographic system downward to a distance measuring device 903. Based on the information of the measured object distance, the photographic lens is adjusted to a certain focusing position. And, as the second stroke of the release button is done, a release actuating signal occurs, starting adjustment of a diaphragm device 904 in the photographic lens to an aperture value previously determined by the output of a light measuring system known to those skilled in the art. At the same time, the first and second optical elements 901 and 902 start to be moved from the viewing position upward to the outside of the photographic optical path by a known mirror drive mechanism. It is after the movements of the diaphragm and the mirrors have terminated (in the state of FIG. 17) that releasing of the shutter is started to make an exposure. The time space from the occurrence of the release signal to the start of the exposure is called the "release time lag", amounting to a range from 100 (mS) in the fast AF cameras to 200 (mS) in the slow one. Even in non-AF cameras, the necessary release time lag ranges from 40 (mS) to 130 (mS). Since this release time lag is the time difference from the moment at which the photographer while looking through the finder has pushed the release button on the chance he thought just right to the actual occurrence of the exposure, a problem arises that for a fast moving object or the like, the intention of the photographer cannot be reflected to the photographs taken.