1. Field of the Invention
This invention relates to photographic cameras with a light measuring circuit adapted to adjust exposure control and operating with a manually operable or automatic film speed setting mechanism, and more particularly to an exposure correction factor setting device associated with such mechanism.
2. Description of the Prior Art
In general purpose photography, the exposure of a photo-sensitive material or film is controlled in accordance with scene brightness. In some photographic situations, as, for example, using flash illumination, however, it is required to modify a photoelectrically derived exposure value by taking into account the reflective characteristics of the environment surrounding an object of principal photographic interest the modification being defined as a correction factor.
It is known to provide an exposure correction factor setting device utilizing a common variable resistor in a film speed dial. With this device, after the given film speed has been set in this resistor, the thus set value of resistance is changed by +1 or -1 in EV to effect either an under-exposure with a decrease of 1 EV from the basic exposure value, or an over-exposure with an increase of 1 EV therefrom. Recently, a manually operable or automatic film speed setting mechanism has been developed, and there is strong demand for imparting into such mechanism the function of the exposure correction factor setting device.
USPTO Backgrounds
USPTO Backgrounds