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Fig. 5. The Rotax high-speed camera, showing its motor side.
High-Speed Photography
During 1952 the Askania factory in Berlin resumed delivery of high-speed cameras. Their large Model No. 4123, illustrated in Figs. 3 and 4, takes up to 2000 frames/sec, and the small hand model Rotax, illustrated in Figs. 5 and 6, takes up to 500 frames/sec. Both of these cameras are again in regular production for industrial research. Optical compensation in the Model No. 4123 is provided by a rotating lens disk. A 16lens disk, producing frames 1 8 mm X 24 mm, is used for speeds up to 1000 frames/sec. For speeds up to 2000 frames/sec a 32-lens disk is used, producing frames 9 mm X 24 mm. Optical compensation remains constant at higher or lower picture speeds. The camera drive consists of an electronically powered d-c motor with excellent regulation regardless of the load.
The Rotax, or hand model, slowmotion camera takes pictures up to 500 frames/sec, 18 mm X 24 mm in size. Its light weight enables the taking of pictures at long focal lengths without support, an advantage which up to now no other camera of such high frame frequency has offered. Since the object
Fig. 6. The Rotax high-speed camera, showing film threading.
can be kept in view while photographing with the Rotax camera, flying objects may be followed and photographed with ease and aerial photography is possible without special installation or mounting. The quality of the picture approximates that of normal motion-picture film. Both of these high-speed cameras are equipped with time recording devices which expose light flashes on the edge of the film at 1/100-sec intervals. These markings are used to establish the frame rate during exposure.
35mm Projection
Standard film projectors are now being produced in Germany by a number of firms. Askania manufactures a new projector called the A.P. 12 (Fig. 7) in which the motor drive belt consists of four cables. The motor is so designed that the four cables are stretched equally over the drive wheel of the windup friction gear to drive the mechanisms in the projector head (Fig. 8). It is claimed that this device considerably reduces the wear on all parts. The shutter is a
George R. Groves: Progress Report Addendum
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