Abstract: A lens barrel standard position detection device, attached to a lens barrel equipped with a fixed tube having a first member and a movable tube rotationally moving back and forth along an optical axis of the lens barrel and having a second member engaging the first member of the fixed tube, to detect when the movable tube reaches a predetermined standard position.

Abstract: When defective pixels of a solid state image pickup device of a video camera are corrected by signal processes, a white spot noise is detected by closing an iris and by comparing the signal level and a level of only a dark current. Further, in this case, a gain of an AGC circuit for controlling a gain of a video signal is raised and a precise detection is executed. By executing such a detecting operation at the time of turn-on or turn-off of a power source, the user is not annoying. In the ordinary photographing, a reference level in detection of a white spot noise is set to an optimum value in accordance with a temperature of the solid state image pickup device or its peripheral temperature or the gain of the AGC circuit so that the white spot noise detection is not influenced by the temperature of the solid state image pickup device or the operating state of the AGC circuit.

Abstract: A video camera capable of switching an aspect ratio and an electronic view finder for use in the same. In response to a switching control signal from an aspect ratio switching circuit, a video signal having a different degree of horizontal compression and an aspect switching control signal are fed to the view finder, a magnetic recording/reproducing circuit and an external device. The magnetic recording/reproducing circuit simultaneously records the video signal and the switching control signal. In reproduction, the magnetic recording/reproducing circuit reproduces and outputs the recorded switching control signal. In response to the switching control signal, the external device changes the deflection angle of a built-in display circuit and switches the aspect ratio to display the video signal.

Abstract: Dithiolane derivatives represented by the formula (I): ##STR1## wherein R.sup.1 is an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, a benzyl group or an alkoxyalkyl group and R.sup.2 is a cyano group, an alkylcarbonyl group, a benzylcarbonyl group, a phenylcarbonyl group, an alkoxycarbonyl group, a cycloalkyloxycarbonyl group, a benzyloxycarbonyl group, an alkenyloxycarbonyl group, an alkynyloxycarbonyl group or an alkoxyalkoxycarbonyl group,and an organic acid ester thereof; process for producing the same; and pharmaceutical composition for controlling liver diseases of human beings and animals containing the same.