Abstract: An exchangeable connecting device between a video camera and an automatic iris lens in which one common connector (k) makes it possible to connect different kinds of lenses, and use any kind of a lens, L1 or L2 without first confirming the kind of lens to be used. In the video camera (M5) one of video control signals (1), amplified by the output of a light sensor is directly connected to an analogue switch (t), while the other is connected through a galvanometer control circuit (p) to the analogue switch (t) by common connector (k). When a video signal control type automatic iris lens (L1) is connected, a video control signal (1) amplified by the output of light sensor is directly connected to the analogue switch (t) and the common connector (k). When a DC control type automatic iris lens (L2) is connected, analogue switch (t) selects a video control signal (1) amplified by the galvanometer control circuit p.

Abstract: Object: To broaden the range of photographing of object, until illumination of 0.02 lux. Construction: In the case of sufficient bright object, photographing is performed by a conventional circuit at a high S/N ratio, at a high degree. In the case of an insufficient bright object, inserting auxiliary amplifying circuit m, m1, m2 or em and ignoring the S/N ratio, and raising the amplification degree. In the case of sufficient bright object, photographing is performed by high S/N ratio, and high degree, in the case of insufficient bright object, an auxiliary amplifying circuit m, m1, m2 or em is inserted ignoring the S/N ratio until utility noise composite of 20 dB (10%).

Abstract: Object: To broaden the range of photographing of object, until illumination of 0.02 lux. Construction: In the case of sufficient bright object, photographing is performed by a conventional circuit at a high S/N ratio, at a high degree. In the case of an insufficient bright object, inserting auxiliary amplifying circuit m, m1, m2 or em and ignoring the S/N ratio, and raising the amplification degree. In the case of sufficient bright object, photographing is performed by high S/N ratio, and high degree, in the case of insufficient bright object, an auxiliary amplifying circuit m, m1, m2 or em is inserted ignoring the S/N ratio until utility noise composite of 20 dB (10%).