CH618264

Disclosed is a light-metering system for an attachment camera of the type particularly adapted for use with an optical observation instrument having an optical axis comprising a mounting means positioned between the observation instrument and the shutter of the camera and being movable in at least two degrees of freedom; optical means positioned on the optical axis of the observation instrument for selectively deriving either an observation beam or a metering beam from the beam path of the observation instrument; a measuring diaphragm mounted on the mounting means and arranged in the image plane of the metering beam; a photoelectric receiver associated with the measuring diaphragm; a set of markings carried by the mounting means opposite to the measuring diaphragm and positioned in the observation beam; means positioned in the observation beam in a plane conjugated with the image plane of the observation instrument for viewing the image superimposed upon the set of markings; and means for moving the mounting means in the at least two degrees of freedom in order to selectively adjust the location on the viewing means of the set of markings which indicates the image area which is to be evaluated from the image field of the observation instrument.