U.S. Pat. No. 5,229,809 (the '809 patent) discloses a camera including a self-timer and an electronic flash. Several embodiments are shown in which the self-timer mode is entered and charging of the flash is commenced even when the flash cannot be fully charged within the time delay of the self-timer.
For example, the embodiment described in FIG. 9 of the '809 patent indicates that the shutter release is prohibited if the charging of the flash is not completed when the time counting of the self-timer is completed (col. 7, lines 1-3). Such an arrangement creates problems in that battery power is wasted and the operator expect that a self-timer picture will be taken when it will not be taken.
In the embodiment described in FIGS. 10A and 10B of the '809 patent, the time delay of the self-timer is extended for as long as it takes for the flash circuit to fully charge. If the batteries in the camera are weak, the amount of self-timer delay can become unacceptably long. During such a long delay, there may be a scene change (e.g. subject movement) which can degrade picture composition quality.
A further embodiment shown in FIGS. 12B and 12C of the '809 patent releases the shutter at the end of the self-timer delay regardless of another flash charging is complete or not (col. 8, lines 51-55). Obviously, such an arrangement can cause underexposed images to be recorded due to insufficient lighting of the scene.
USPTO Backgrounds
USPTO Backgrounds