| 摘要 |
PURPOSE:To make it unnecessary to hold the lens during range finding to make it possible to shorten the time for focusing, by obtaining and correcting the finding error caused by lens movement. CONSTITUTION:The light beam from the object is incident to photoelectric elements A1-An through mirror 20, lens 21, and prism 22, and is incident to photoelectric elements B1-Bn through mirror 23, lens 24, and prism 22. Photodiode arrays CCd, BBD, and so on are used in photoelectric element groups A1-An and B4-Bn. The defocus signal corresponding to phase slip j' of patterns A and B formed by outputs of photoelectric element groups A1-An and B1-Bn includes the error indicated by the two-dots chain line or the one-dot chain line in the figure when the lens is moved in a constant speed. Then, the true value is calculated from the range finding value of the defocus signal to control movement of the lens, so that range finding is possible while moving the lens, and the time required for focusing can be shortened. |
