As film and mechanical transports improved, the high-speed film camera became
available for scientific research. Kodak eventually shifted its film from
acetate base to Estar (Kodak's name for a Mylar-equivalent plastic), which
enhanced the strength and allowed it to be pulled faster. The Estar was also
more stable than acetate for more accurate measurement, and it was not as prone
to fire.
Each film type is available in many load sizes. These may be cut down and
placed in magazines for easier loading. A 1200 foot magazine is typically the
longest available for the 35 mm and 70 mm cameras. A 400 foot magazine is
typical for 16 mm cameras, though 1000 foot magazines are available. The images
on 35 mm high speed film are typically rectangular with the long side between
the sprocket holes instead of parallel to the edges as in standard photography.
16 mm and 70 mm images are typically square rather than rectangular. A list of
ANSI formats and sizes is available.
Intermittent pin register
The intermittent pin register camera actually stops the film in the film gate
while the photograph is being taken. In high speed photography, this requires a
complex mechanism for keeping the film moving quickly through the camera from
the supply reel, but then stopping it for imaging, and then starting it again to
move it onto the take-up reel. In many cases, a loop is formed before and after
the gate to create and then take up the slack. Pull-down claws grab the film and
move it into place and then move it back out of the film gate after the
exposure. Register pins secure the film while it is being exposed. In some
cases, vacuum suction is used to keep the film, especially 35 mm and 70 mm film,
flat so that the images are in focus across the entire frame.
* 16 mm pin register: D. B. Milliken Locam, capable of 500 frame/s; the
design was eventually sold to Redlake. Photo-Sonics built a 16 mm pin-registered
camera that was capable of 1000 frame/s, but eventually removed it from the
market.
* 35 mm pin register: Early cameras included the Mitchell 35 mm.
Photo-Sonics won an Academy Award for
Technical Achievement for the 4ER in 1988. The 4E is capable of 360 frame/s.
* 70 mm pin register: Cameras include a model made by Hulcher, and
Photo-Sonics 10A and 10R cameras, capable
of 125 frame/s.
Rotary prism
The rotary prism camera allowed higher frame rates without placing as much
stress on the film or transport mechanism. The film moves smoothly past a
rotating prism which is synchronized to the main film sprocket. Each revolution
of the prism "paints" the same number of frames onto the film as there are faces
on the prism. A shutter also improves the results by only opening as the prism
faces are nearly parallel, and then closing again.
* 16 mm rotary prism - Redlake Hycam and Fastax cameras are capable of 10,000
frame/s with a full frame prism (4 facets), 20,000 frame/s with a half-frame
kit, and 40,000 frame/s with a quarter-frame kit.
* 35 mm rotary prism - Photo-Sonics 4C
cameras are capable of 2,500 frame/s with a full frame prism (4 facets), 4,000
frame/s with a half-frame kit, and 8,000 frame/s with a half-frame kit.
* 70 mm rotary prism - Photo-Sonics
10B cameras are capable of 360 frame/s with a full frame prism (4 facets), and
720 frame/s with a half-frame kit.
Some of the Photo-Sonics Film
cameras mentioned above are still in regular use within the movie industry to
this day. Full after sales support is still available for most models. For
support, please visit our
technical support page or contact us at the addresses below.
