19-06-1990 дата публикации
Номер: US4935763A
When a variator lens is driven to effect zooming, focal length information of a zoom lens unit, a zooming direction and a defocus amount are detector. Integration in CCD for focus detection is regulated in a short time during zooming and a cycle of focus detection is set to a predetermined period. A moving speed of a compensator lens is controlled based on detected information. A moving range of the variator lens is divided into zones and a basic moving speed of the compensator lens is set for each zone. When the variator lens is driven and information obtained by focus detection or a zooming condition corresponds to a specified condition, the compensator lens is moved at a basic speed corresponding to the zone where the variator lens exists or at a moving speed of the compensator lens applied till then. Focus detection areas automatically changed dependent on a situation of an object are forbidden to be changed during zooming. In addition, a focus detection are indicating mark displayed in a finder of the camera is fixed and unchanged during zooming irrespective of actual change of the focus detection area.
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