JPS56122003A - Zoom lens barrel capable of selection of operating part - Google Patents

Abstract

PURPOSE:To obtain a simplified zoom lens barrel, by exposing a part of the cam barrel enabling the zooming operation of the operating ring over the outer circumference surface of the lens and then displaying the figures or index lines on the exposed part of the cam barrel for the purpose of measurement. CONSTITUTION:When the operating ring 36 is moved toward the optical axis, the lens optical system I moves back and forth via the screw connections 36a and 38a of the intermediate barrel 38 plus the helicoid connections 38b and 42b. With a shift of the barrel 38 toward the optical axis, the cam barrel 37 turns round the optical axis by an engaging function between the cam groove 37a and the rectilinear groove 34a of the pin 35. As a result, an engagement is secured between the cam groove 37b and the rectilinear groove 34b of the pin 46 of the lens holder 49. Thus the lens optical system II moves to perform a zooming action. The distance figures (unit: f, t & m) are displayed at the end part 36c of the ring 36; the focal distance, the standard index 37d, and the index line of depth of field before and after the index 37d are displayed at the exposure part 37c of the cam barrel 37; plus the index line 34c and the value of iris diaphragm are displayed at the base barrel 2 and the ring 33 respectively. In such way, the barrel can be simplified for a zoom lens.