The invention relates to photographic flash apparatus, especially but not exclusively for photographic studios, the flash equipment having provisions for exposure measurement and automatic flash limitation. More particularly, the invention relates to equipment having a plurality of separate flash units, so that at the time of the photographic exposure, the subject being photographed (and its background) may be illuminated by light coming from two or more directions, each flash unit having an ignition and quenching device, there being exposure-measuring apparatus which measures the light reflected by the subject to the camera, and instigates the interruption or termination of the flash radiation when a determinable light value is reached.
In such a flash arrangement, the overall illumination impression of subject and background is detected by the exposure-measuring apparatus independently of the desired distribution of the individual light fluxes of the respective flash units, and the flash radiation can be broken off or terminated at any desired moment, according to the desired overall illumination detected by the exposure-measuring apparatus. It is essential here that all flash units should light up and extinguish simultaneously without time delay or with no substantial time delay. Thus it is insured that the light distribution desired on the subject, which can be produced by differently selected positions of the individual flash units, are correctly reproduced in the exposure.
A known flash arrangement of this kind comprises an exposure-measuring and flash-limiting apparatus fitted close to the camera, which apparatus is connected with the synchronous switch of the camera shutter and controls the simultaneous ignition of all flash tubes and the simultaneous tripping of all extinguishing arrangements in the connected independent electronic flash units. The individual flash units are connected with one another with the exposure-measure and flash-limiting apparatus by two-core cables.
Since the laying of cables is extremely hindering in studio operation, in a further known flash arrangement of the initially stated kind the simultaneous ignition and extinguishing of all electronic flash units are effected by an exposure-measuring and flash-limiting apparatus which radio-controls the ignition and extinguishing devices of the individual electronic flash units through remote control transmitters and remote control receivers. Such remote control transmitters and receivers however are very expensive and hardly find acceptance in flash arrangements for simple studio installations, on account of their high costs.
The invention is therefore based upon the problem of producing a flash arrangement of the initially stated kind in which the ignition and extinguishing of the individual electronic flash units take place without connecting cables, on the one hand, and on the other hand no particular remote control transmitter is required, and the technical expense of which is substantially reduced in comparison with the known flash arrangements.
USPTO Backgrounds
USPTO Backgrounds