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EVOLUTION OF PROFESSIONAL CAMERA
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same inventor later designed the Debrie super-speed camera, which is used extensively abroad.
At the same time, America was following the path of progress. Since space does not permit us to enter into details of the research work and the results obtained in ultra speed cinematography for use of research laboratories, we may mention that the first super-speed mechanism capable of taking as many as 200 pictures per second for
Fig. 5 Bell H Howell Registering Intermittent Mechanism. A — Pilot Registering Pins. B — Floating Shuttle Fork Bearings. C — Film Feeding Shuttle Fork Bearings. C — Film Feeding Shuttle Fork. D — Register Leaf Operating Cam Roller. E— Mounting Plate. F — Back Register Leaf Work Arm. G— Film Feeding Fingers. H — Shuttle Guide Holder. J — Back Register Leaf. The film is disengaged from the pilot registering pins at the moment that it starts its motion, through a backward motion of the register leaves controlled by cam action. The up and down motion of the shuttle is secured through the heart-shaped cam of the camera mechanism. Absolute register of each picture is assured by this mechanism
commercial work was devised in America by Mr. Howell, who, with a view to practical achievements, succeeded in making it part of the standard Bell & Howell camera, so that the same apparatus could be used for both ordinary and super-speed work.
The average rate of speed at which miniature scenes are taken is 128 frames per second, that is to say a speed eight times the normal speed. The considerable increase of the intermittent movement involved complex mechanical problems in consideration of the fact that none of the attributes of film safety and perfection of registration could be sacrificed.
Mr. Howell, in his super-speed mechanism, imparted the movement to the film by means of four pairs of pawls actioned by an eccentric driven by two gears, one of which is solidary part of the camera cam and gear shaft. The accuracy of film registration is secured by a pair of check-pawls which engage in a pair of perforations and stabilize the film at the end of each stroke of the pawls.
The lateral registration of the film is secured in this mechanism by a novel and carefully calculated "side tension" resulting from the action of a spring controlled floating rail upon one edge of the film, while the opposite edge is held in position by a stationary rail. This side tension system permits leaving a clearance between the film surfaces and the walls of the film channel. The elimination of friction