This invention relates to an electric shutter operating circuit for use in photographic cameras.
The electric shutter operating circuit for use in photographic cameras is constructed to connect the amount of the light received from an object into an electric signal, to determine the photographing conditions commensurate with the brightness of the object in accordance with the electrical signal, to indicate to the user whether the iris opening and the shutter time are correct or not and to control the operation of the shutter.
In the past, various types of electric shutter operating circuits have been proposed, but prior art circuits were constructed to indicate the correct value or incorrect value of the exposure for a particular brightness of the object by merely representing over exposure and under exposure or correct exposure to the user of the camera. Accordingly, in the former case, absence of the display of the over or under exposure means the correct exposure. However, the correct exposure is also not displayed in a case of the fault of electric power source or electric circuit thus resulting in the failure of photographing or giving a feeling of uncertainty to the user. In the latter case, where the exposure is incorrect, the user cannot judge whether the exposure is over or under.
Furthermore, in the prior art electric shutter operating circuit, as the shutter control circuit and the exposure display circuit were provided independently, there was a defect that the entire circuit was complicated and expensive.