| 摘要 |
PURPOSE:To increase a dynamic range based upon the brightness of a subject and to perform focus detection in a short time by adding vertical signals as many as lines in an image sensor when the brightness of the subject is low and widening a distance measurement area. CONSTITUTION:The signals of photodetectors are added by an adding means 5 in the photodetecting device 10 and a capacity varying means 6 varies the capacity of the charge transfer part of a transfer means according to the quantity of light which is incident on the photodetectors. Then the charges added by the adding means 5 are averaged by an averaging means 7 and read out. Thus, the outputs of the photodetectors are read out at a time for the focusing of the low-brightness subject, so the SN ratio is improved and when the distance measurement area is varied, the capacity of a horizontal transfer part is varied, so the amount of handled charges increases. Consequently, a subject brightness range is widened, the changing of the distance measurement area is easily handled, and the focus detection time becomes short. |
