Camera body with electrical contacts for connection to attached lens

摘要

A communication device has two modes. In one mode it receives predetermined information, and in a second mode, it transmits predetermined information. The first mode uses a set of contacts (A) on the body, if a lens which allows the first mode is attached. The second mode uses a set of contacts (B) which includes set A, when the attached lens allows the second mode. An identification device determines if the attached lens allows the second mode, by detecting the electrical potential of one of the contacts. A photographic lens and a camera system are also claimed.