With the ongoing development of technology, digital products, such as digital cameras, PDAs, or digital video cameras, have become more widely used. In poor light conditions, such as on a cloudy day, a photoflash is necessary to obtain a quality image. The photoflash generally comprises a lamp and a capacitor. When the photoflash is used, the capacitor discharges causing the lamp to flash.
Referring to FIG. 3, a related photoflash apparatus 100 includes a light sensitive element 10 for converting light signals to electrical signals, a signal processor 12 for receiving the electrical signals to output the brightness (Y) information, a comparing unit 14, a calculating unit 16, and a photoflash module 18. The photoflash module 18 includes a lamp 17 and a capacitor 19. The capacitor 19 is discharged to make the lamp 17 flash to provide additional light for the image. The comparing unit 14 is configured for comparing a current brightness value with a predetermined brightness value stored in the comparing unit 14. When the current brightness value is less than the predetermined brightness value, the calculating unit 16 calculates the photoflash time of the photoflash module 18 based on the brightness Y. The calculating unit 16 outputs the photoflash time to control the photoflash module 18.
However, when the calculating unit 16 calculates the photoflash time, the second voltage value of the capacitor 19 is gradually reduced. The photoflash time calculated by the calculating unit 16 is based on a first voltage value of the capacitor 19. However, the capacitor 19 has been discharged to provide additional light. Therefore, the residual voltage of the capacitor 19 is not enough to provide sufficient brightness during the photoflash time.