| 摘要 |
PURPOSE:To shorten the necessary time of focusing by outputting data which is different in focusing permissible width depending upon whether a teleconverter is mounted or not between an interchangeable lens and a camera body. CONSTITUTION:Whether the teleconverter COV is mounted or not between the interchangeable lens LE and camera body is detected; when it is mounted, a focusing state is detected on the basis of data with larger focusing permissible width than when the teleconverter is not mounted. Therefore, even if variation in the defocusing quantity of the lens LE with respect to the unit movement extent of a focusing optical system increases owing to the mounting of the converter COV, the lens is prevented from moving out of the focusing permissible width range easily, and the necessary focusing time is shortened. Further, the mounting of the converter COV increases the effective aperture value of the whole photographic optical system to increase the depth of focus, so that even when the focusing permissible width is increased, a decrease in practical focusing detection precision is prevented. |
