Intervals timer for cameras

Interval timer for periodically providing a camera with a release signal to control the photographing operation thereof by carrying out one exposure cycle and a successive automatic film winding operation in response to each release signal from the interval timer, comprising:

• means for periodically producing a release signal;
• means for setting the interval between the occurrence of the successive release signals;
• first and second terminals to be connected with the camera, the release signal being transmitted to the camera through said first terminal;
• means responsive to a first reply signal at said second terminal transmitted from the camera for examining the timing of the arrival of the first reply signal to said second terminal to determine whether or not the examined timing falls into a predetermined condition for controlling the operation of said means for producing, said examining means is further responsive to a second reply signal at said second terminal transmitted from the camera subsequent to the first reply signal, and includes first means for measuring a first period between the arrival of the first and second reply signals, and the predetermined condition is that the measured first period is longer than a first predetermined timer period;
• and
• means responsive to said examining means for interrupting said producing means from producing the release signal when the examined timing falls into the predetermined condition.