The Camroc was a marvel in simplicity with only one moving part: the shutter. It took one shot per flight using special disks of film loaded prior to launch. The shutter was tripped when the ejection charge fired to release the parachute. The idea was to use a rocket engine with enough of a delay between launch and parachute deployment to ensure that the rocket was in a nose-down attitude when the shutter fired, thereby obtaining a shot of the ground below. (catalog photo from www.ninfinger.org)
At the far left is my Camroc in disassembled form, along with an unused (but exposed) film disk in its light-proof envelope. Next to the envelope is the metal “slide” that was removed from the camera just prior to launch. The picture at the not-so-far left is from the instruction manual and clearly labels each part
The film disks were approximately 1.5 inches in diameter. It was ASA 400 film that needed to be “pushed” to ASA 1200 through extended processing times. Using readily available photo processing chemicals and a darkroom, a hobbyist could process the film. Or, the film could be sent to Estes for processing.
On left is a close-up of the lens from the side facing the film plane. On the right is the other side of the same section showing the shutter spring (rubber band) pins and the aperture of the shutter in the “open” position. The shutter was held in the cocked position with a string that went under the camera body at the narrow end that went into the rocket body. When the parachute was deployed, the camera separated from the rocket, releasing the string thereby releasing the shutter.
This is another catalogue shot showing the Camroc along with its sister photographic payload, the Cineroc movie camera. There is also a picture of the Estes Camroc Carrier rocket (catalog photo from www.ninfinger.org)
This is my attempt to make an Astron Delta clone. This was a two-stage rocket that was recommended by Estes as the carrier of the Camroc. This was prior to the introduction of the Camroc Carrier rocket above. (catalog photo from www.ninfinger.org)
This is I real Astron Delta recently found in an old-time hobby shop. The original price is $2.50. One sold on ebay recently for over $100!
September 17, 2010: This Camroc probably hasn’t snapped a photo in 40+ years. Was it up to the challenge this many years later? To answer this burning question, our Camroc needed a little TLC to get some obvious repairs made.
First, there is the rubber band powered shutter. In flight, the shutter is snapped open and closed by a small rubber band. After 40+ years, the original rubber band has gone missing. Even if it had remained, it would likely need replacing due to a common case of dry rot. A bag of #9 rubber bands from any office supply house will do the trick. Secondly, some fresh tape to hold all of the Camroc sections together. I used a combination of black and yellow electrical tapes to do the job. The yellow tape is not required, since the black can be used , but the yellow gives the Camroc that factory-original appearance.
The circular film. Hmmm, this is a tough one. I can’t get it from Estes these days, since the Camroc went out of production in the 1970′s. I’ll have to make my own. The original Estes Camroc film disk was a 1-9/16 inch disk of ISO 400 film of unknown origin. I can use modern sheet film (used for medium and large format photography using a view camera) and try cutting out the disk manually somehow. I could try doing it with scissors, but I’d have to do it in total darkness, and I’m guessing that a perfect circle under those circumstances would be unachievable.
The next best thing is this 1-1/2 inch hole punch from Ek Success. Unfortunately, there is no 1-9/16 inch hole punch out there (that I know), so I’m going to have to make some modifications to the Camroc’s film holder to use the smaller disk.
First was the area behind the lens. Using the computer, I drew to circles, one at 1-9/16 inch in diameter, the other at 1-1/2 inch. I lined them up on edge and printed them out. This would give me a pattern for circular, crescent-shaped “lip” to hold the film in place from the front. I glued the pattern to some thin sheet styrene plastic (1/16 inch) and was able to cut the crescent shape out with scissors. I then used CA “instant” glue to glue the crescent to the back of the lens section.
You can see the plastic “crescent” glued in place behind the lens section. The thin plastic can be easily shaped in place once mounted by using a hobby knife to “shave” off excess material and get a good “arc”. To hold the film in place from the back, I modified the film holder with these plastic strips glued in place and lined up with the film holder’s original retainer lip. These two modifications gave the smaller film disk something to rest between and secure it during flight operations.
I purchased some Ilford HP5 Plus ISO 400 black-and-white film in a pack of 25 4×5 sheets. This along with the hole punch should give me plenty of film disks.
The moment of truth. I cut myself a few film disks, and after fumbling around in the dark, managed to get a few loaded for some sample pics. The Camroc only shoots one photo per launch, so a new disk must be loaded after each flight.
In order to do this at the launch site, you’ll need a film changing bag. This is essentially a black, light-proof bag you can stick your film items in, put your hands through two tight fitting holes in the bag, and perform various tasks that would otherwise need to be done in a darkroom.
Here is a paper 1-1/2 inch disk sitting in my modified holder. It’s essentially pushed to one side a little off center. Trying to center it is nearly impossible given the holder design. It would be far more effort to come up with such a modification than it was to simply put it off center.
Success! These are some test shots I took on the ground of my house. I processed them at home using readily available black and white processing chemicals. The exposure seems correct, so it looks like the #9 rubber bands are the perfect replacement for the original. The photos are fairly sharp, so I know my modified film holder is doing its job. I have to say, the photos are actually sharper than I expected. The single element plastic lens of the Camroc seems to be better than that of the early Astrocam. Only the latest Astrocams seem to be on par.
I am currently constructing an Estes Camroc Carrier clone using parts (including laser-cut fins) from Semroc. Semroc is a good source for discontinued model rocketry kit parts.
Time to fly. It was a beautiful fall day here – sunny and a tad chilly at 50′F – great for the Camroc and newly-built Camroc Carrier clone model rocket. Armed with a half-dozen film disks and Estes C6-5 engines, I was looking forward to a visit into model rocketry’s past. The wind was a touch high today, but the sun was shining bright, we had a very large field over in Ivyland, PA, and my friends, Scott and Justin, were also there to launch some of Scott’s rockets. I had only brought my Camroc and I expected that to occupy my time fully with launch prep, launching, recovery and reloading with film. Film reloading is an interesting chore, and has to be done in total darkness. The only way to do this at the flight field is in a light-tight film changing bag. The changing bag is black, light-proof treated fabric bag with two holes to insert your arms through and perform the film changing.
I spent the better part of the week finishing the Camroc Carrier, built from a collection of reproduction parts from Semroc rocketry, and while it was indeed a rush job to get it ready for launch day, it still turned out presentably.
Unfortunately, that’s were the good feelings ended. Later on that night, I processed the film and was disappointed to find that no usable images were captured. Here is a sample of four of the negatives:
All of them are over-exposed. It seems as though there was some light leakage somewhere, either in the Camroc, or the light changing bag or both. It could also be that the shutter is not closing quickly enough. When I took test photos about two months ago, the tests were fairly controlled in that the film was loaded inside the house in dark storage room in the basement, and the rocket didn’t spend more than a few minutes outdoors while I took the shots.
So, it’s back to the drawing board to do some more tests to look for light leakage and/or a malfunctioning shutter. That is all for now. Fooey.
Originally posted 2007-10-14 18:03:27.
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