Rotating Drum Camera

Rotating Drum Camera

Author: Tim

For my other UMD research, high-speed imaging is necessary, so I set out to find an inexpensive and robust high speed imaging method. Current state of the art systems are many hundreds of thousands of dollars and were simply out of reach. However, after several years, a few eBay finds and some repair, I was able to get an old Cordin Model 350 Rotating Drum Camera up and running. The folks at Cordin have been super kind and generous with what little information they have left. Prof. Andrew David-Hazy of RIT has also been super supportive and helpful as he has an similar but older Dynafax camera.

It was explained to me that the last person in the world that knew how to load one of the film cassettes had died a few years back. So, my bold assertion is that I am the only human left that knows how to load one of these up. Since this technology is all but lost I have made a recording of loading and unloading film into the Model 350.

The Cordin Model 447A controller, with an oscilloscope on top to monitor frame rate, and the Cordin Model 350 rotating drum camera.
This is a video of the Cordin 350 spinning up, testing the new camera-controller cable harness I built.
From the instruction manual: labeling of major components
From the instruction manual: the optical path. Note items 5, 10 and 10′ – these are crucial “stops” that were missing from this camera.
Inside the Model 350
From the instruction manual: labeling of internal components
Again, note the missing exit stop that would mount in the two slots.
Also note missing entrance stop which would have been mounted under the entrance relay mirror
The Model 350 project was on hold until this Beckman & Whitley Dynafax camera came along on eBay. Since its construction is nearly identical, it was hoped that its stops could be scavenged. It indeed had the stops, but the mounting was total different. At least some dimension now became available, such as the thickness and diamond apertures of the stops.
This is the capping stop from the Dynafax.
It was about 0.010inches thick.
After careful reverse engineering, the machine shop was then able to replicate the stops with appropriate mounting for the Model 350.
This was a precision job that worked the first time. Note the exit stops sitting upside down just to test their mating to the Model 350’s alignment pins.
From the instruction manual: labeling of the film cassette and its mounting bezel.
From the instruction manual: The film partially loaded into the cassette
Here is a short video I made on loading the Cordin 350 film cassette, then loading the camera drum with the film, then retrieving the film from the camera.
From the instruction manual: while the camera uses 35 mm film, it does not put down a full frame that normal 35 mm users would expect, rather in one 34-inch long loading, the camera makes 224 small circular exposures, two rows of 112 images. Because of the angular separation between the upper and lower optical paths, the upper and lower sequence of images are offset by 7 images.
It was time for a test with the newly installed entrance and exit slits. Tim’s old soviet stopwatch was used as a test subject.
It works! A but underexposed, but none-the less, a sequence of in-focus images of the stop watch forms.
Using the Bessler enlarge, a few of the small frames were projected and captured with a cell phone camera.
From the instruction manual: a useful guide to determining exposure rate for the Model 350.