Interchangeable lens

Abstract

Abstract PURPOSE: To transmit the focal length information of an interchangeable lens extending over a wide range to the camera body without increasing the size of the camera by providing a signal member of the signal quantity corresponding to logarithmic focal length. CONSTITUTION: A detecting lever 17 contacting the signal member 12 of the signal quantity proportional to the reciprocal of the logarithm of the focal length of an interchangeable lens mounted to the camera body turns according to the extention of the projection of the member 12 and the focal length is converted to a digital signal by way of digital code patterns 21a, 12b.... This signal is transmitted to the camera body. The relation between the amount of projection and the focal length is made linear by this signal quantity corresponding to logarithmic focal length. Hence, the difference l in the extent of projection of the member 12 of the case when a certain focal length is made M times becomes always constant, thus the focal length of the interchangeable lens of which the focal length extends over a wide range may be transmitted to the camera body without increasing its size. COPYRIGHT: (C)1981,JPO&Japio

Inventors

• 👤 Sunao Ishizaka
• 👤 Toshiaki Hoizumi

Bibliographic Details