PURPOSE: To take always photographs under prescribed brightness, by changing the zooming range of a zoom lens in accordance with the condition of aperture values.
CONSTITUTION: A diaphragm position signal of a diaphragm position detecting circuit 1 is digitized through an AD converter 2 and a signal voltage for stopping zooming operation correspondingly to a zoom stopping position fN is supplied from a zoom stopping position setting circuit 3 to a zoom end stopping circuit 5 in accordance with the digitized signal. The zoom end stopping circuit 5 compares a zoom position detecting signal from a zoom position detecting circuit 8 with the signal from the zoom stopping position setting circuit 3 and detects whether it is still in a movable area in the zooming range or stopping area. When the zoom operation enters the stopping position, the circuit 5 forcefully makes a zoom control signal to be given to a servo amplifier 6to zero and stops the zooming operation being carried by means of a zoom motor 7.
| JP3448403 | ZOOM LENS |
| JP3875823 | EYEPIECE ATTACHING/DETACHING DEVICE FOR OPTICAL EQUIPMENT FOR OBSERVATION |
| WO2005119334 | VARIABLE FOCAL LENGTH LENS |
ONUMA TAKASHI
SEKIGUCHI TAKESHI
| JPS59359U | 1984-01-05 | |||
| JPS4819415A | ||||
| JPS5348728A | 1978-05-02 |
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