Zoom lenses

Zoom lenses

4.11 - 1251 ratings - Source

The d.c. motors with permanent magnets can be run at a very low speed if the load is small and if measures are taken to ... an iris diaphragm, with servo-drive and electronic system built into the lens, and Schneider Servo modules controlling both zoom and focus controls. ... Manual operation by the cameraman is still a problem, since the zoom lens is usually well out of reach on the front of the camera.

Title:Zoom lenses
Author:Alan Dennis Clark
Publisher:CRC Press - 1973


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