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Early Box-type Bell and Howell (1907)
ing turret carrying four lenses — in early practice, two matched pairs oi different focal lengths. The lenses of each pair were arranged opposite each other across the turret, so that while one lens was being used for taking, the other might be used as a finder. Since the ground glass of the finder was in exactly the same focal plane as the film, a lens focused on the finder could then he swung over and used for taking. The problem of parallax was overcome by having the whole camera slide over on the tripod head so that the finder lens would be in the same position it would later occupy when the picture was being shot. Once focused at the finder, the lens was then swung over, the camera slid back to its normal position, and everything was set.
The dissolving shutter may not have been the first ever used, but it was probably the first actually to reach the market. Certainly it made the industry sit up and take notice. The only camera prior to the Bell and Howell with an automatic dissolve was the Pathe Professional, with its
lens diaphragm coupled to the mechanism. A lens dissolve had two disadvantages, one of which was the visibly increased depth of focus as the lens was closed.
The other bad feature was that a lens fadeout never — as a rule — was quite complete, especially when shooting in strong sunlight. Some cinematographers resorted to speeding up on the crank at the end of a dissolve to further cut the exposure; this caused a slowing down of the action which was sometimes quite effective, in other cases merely comic. Another device was the insertion of a special diaphragm blade which had a small projection which would completely close the lens at the smallest aperture; this was fairly satisfactory.
In passing it might be remarked that the first shutter dissolves used with artificial lighting caused plenty of headaches. In those days alternating current was used for lighting the sets, and the shutter aperture as it was cut down used to get in step with the 60 cycle current. The result was not a smooth fadeout, but a
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