Isoflash-Rapid C

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The Agfa Isoflash-Rapid C was manufactured beginning around 1966 by Agfa Camera-Werk in Munich, Germany. It was made for Agfa's special Rapid cartridge system, intended to simplify film loading. As used in this camera, each Rapid roll yields sixteen 24×24mm exposures. The Isoflash-Rapid C is basically the Iso-Rapid C rebranded for distribution in the USA, through an Agfa affiliate based in Teterboro, New Jersey. It was clearly offered as alternative to the Instamatic series from Kodak which also promised easy drop-in film loading.

Like Afga's other "Iso" models, this version has a hard-cornered, boxy shape, and is mostly constructed of plastic molded with a waffle texture. The top cover and bottom plate are satin-finish metal accents, fabricated from aluminum.

As the "C" in the name implies, the Isoflash-Rapid C offers a flash option in the form of regular flashcubes. The flash is powered by a small 6.3 volt mercury battery concealed under the camera's metal base plate and a capacitor internally; but all other functions are entirely mechanical. To the left of the viewfinder a flash guide is stenciled on the back of the top cover of the camera. This gives gives the recommended subject distance for AgfaPan, AgfaColor, or AgfaChrome film (5-10 feet) when using the flash cubes. Agfapan IF was 17 DIN (40 ASA) B&W film, Agfa Color (CNS) was 17 DIN (40 ASA) Color Negative film, and AgfaChrome (CT18) was 18 DIN (50 ASA) Color Transparency film. The Isitar lens has a single fixed aperture, nominally f/8.2, and is fixed focus. The Parator shutter offers two speeds: “Sunny” (1/80 sec) and “Shade/Cloudy” (1/40 sec).

The flash cube socket on the left of the top cover, the black shutter button on the right top. The film counter is an open window in the top metal cover, which shows the film counter dial. The film counter starts at A, has two dots, then starts counting down from 16 to 1. The camera back opens with a small sliding piece on the right edge of the camera, by sliding the triangle (arrow) downward. The bottom cover removes easily with a coin or fingernail in the cover slot at the rear middle back of the bottom cover. The battery compartment is under the bottom cover, and an insulating piece of brown plastic has a "+" mark to indicate the polarity of the installed battery. The battery, originally a mercury 6v type PX-23 battery, is only used to fire the flash. A metal loop sticks out on the right side of the camera for attaching a carrying strap and there is a tripod thread in the middle right of the underside of the camera, which is also used to hold on a camera case.



The camera has two interlocks allowing the camera to advance the film and the shutter to be triggered, one interlock sensing closure of the rear door and one sensing the presence of film. The rear door interlock is a small metal tab just to the right of center in the upper rear door light blocking channel. The film sensing interlock is a small metal tab just above the film advance sprocket, right next to the film direction arrow. When the rear door interlock is depressed, the film advance thumb-wheel will turn just enough to advance one frame of film, but the shutter will only trigger if the film sensing interlock is depressed also. Any piece of regular 35 mm film can be used to check the operation of the camera, even a short 5 frame piece of developed film, which can be wound 1 frame length and it depresses the film sensing interlock (with the rear door closed) to allow the shutter to fire.

In summary the operation of the camera has these 4 situations:

A. Back door open, no film in the camera: Film advance thumb-wheel turns without stopping, shutter will not trigger.

B. Back door closed, no film: Film advance thumb-wheel turns to advance one frame of film and stops, shutter will not trigger.

C. Back door closed, with film loaded, film advances one frame and the shutter will trigger. This repeats for the entire 16 (18) frames of the standard length Rapid film cassette with the frame counter counting down from 16 to 1 (A - - 16 to 1).

D. Back door closed, with film loaded, at the end of the film. When the shutter is triggered at frame #1, the picture is taken. Then the film advance thumb-wheel will continue to advance the film without stopping until the film has been pushed past the film sensing interlock into the receiving cassette, at which point the film advance wheel should stop (reverts to case B, above). When the back door is open, the film end tail is visible in the "empty" cassette on the left side of the camera.

The Agfa ISOFLASH-RAPID C requires that the shutter be triggered before the film advance thumb-wheel can advance film for each frame, including the beginning frames. When the rear door is opened the film counter resets to "A". With film in the camera and the rear door closed, the film advance thumb-wheel advances roughly one frame and then stops and the film counter rests on the first of two dots between A and 16. The shutter must be triggered to further advance the film. This pre-count picture will be half or all overexposed by the loading process unless the camera was loaded in complete darkness. After the shutter is triggered and the film has advanced twice from the initial loading, the counter will be at 16 indicating the 1st of the 16 frames normally available on standard Rapid film cassettes. If the camera were loaded in complete darkness it would be possible to have 18 exposures on a normal length of Rapid film.

Hand loading film hack

Hand loading of the film presents risk to scratch or bend or kink the film, when trying to push the film into the empty cassettes by hand. An easier way to load pre-cut lengths (~24" is standard) of film into Rapid or SL cassettes is to use the camera itself to push the film into an empty cassette.

In a darkroom; Unroll and cut 24" of bulk 35 mm film using 2 discernible marks on a flat work surface. Then roll the film tightly into a roll smaller than a Rapid cassette and place it into the right side of an ISO Rapid camera that has an empty Rapid or SL cassette in the left side. Close the door with the film in place so it will advance. Advance the film and trigger the shutter for all 18-19 frames, then continue winding the film until it stops winding. Open the camera back and remove the loaded cassette from the left side, load a new empty cassette into the left side and repeat the process for subsequent cassettes. After all cassettes have been loaded, and the bulk 35 mm film safely wrapped, the darkroom lights can be turned on. The loaded cassettes will contain the un-exposed newly loaded film and can be used as a new loaded cassette in the future. Trim the end of the film similar to the ends of the Agfa Rapid film to allow easier loading. NOTE: this method will not work for loading DCS type cartridges.

Rapid, SL, or DCS cassettes

The fact that the ISOFLASH-RAPID C camera has no exposure meter and is basically a daylight camera (or uses flashcubes) can be a minor advantage for not using the correct Rapid film cassette. Any Rapid film cassette can be used for the new (loaded) cassette in the right side of the camera, regardless of its ASA tab length -letter code. A SL System type or DCS (Disposable camera system?) (reference to DCS in Rapid cameras) type cassette can also be used for the new (loaded) cassette . The DCS cassette may require some cardboard shims to hold the cassette in the proper place to feed film, since the DCS cassette is smaller than a Rapid or SL cassette, but the DCS cassette will feed film without problems.

Either the Rapid or SL cassette can be used in the left side of the camera for the empty receiving cassette. The DCS type cassette does not have the internal spring film coiling of the Rapid or SL cassette, and can not be used in the left side as an empty receiving cassette. The film will jam after only a few frames have been exposed. This implies that if DCS cassettes are used, an equal number of empty Rapid or SL cassettes must be available to receive the exposed film. Another way to think of this is that for any number of loaded Rapid or SL cassettes, plus one empty, an additional roll of film in a DCS cassette can be carried, but it must be the last roll used.

A 17 or 18 DIN (40 or 50 ASA) film should be used to load Rapid, SL or DCS cassettes for use in the early Agfa Iso cameras which do not use the ASA tab. Or Higher DIN/ASA film can be "pull" processed to 18 DIN.

Thin film and longer rolls

Some modern 35mm films may have problems advancing the film in Rapid film type cameras, specifically longer than normal lengths of film, since these cameras push the film into the empty cassette and the thinner modern film does not have as much stiffness overall or strength at the sprocket holes. The original Agfa films used in the Rapid cassettes use a thicker base film and have stiffening dimples that Agfa applied to the beginning and end of the film. Longer film loads (beyond the normal 16(18) 24×24 mm frames) may also have problems due to the higher force required to push the film into the nearly full cassette. The SL cassettes seem to receive film better than the Rapid cassettes, and could be used with a longer film load.

When using a longer film load it is necessary to open the back of the camera and reset the film counter when the last (#1) picture has been taken, since once the film counter reaches "1" in normal use, the film advances to the end without stopping. With a longer than 16 exposure film load, this would just waste the additional frames available by the longer film load, unless the counter is reset to "fool" the camera into thinking it has a new cassette of film.

To overcome this: when the #1 frame picture is taken, the camera back should be opened and closed, obviously in complete darkness. The back only needs to be opened a very small amount to allow the counter to reset, so this could be accomplished inside a handbag or wrapped up jacket. When the door is opened sufficiently, the counter resets to "A" and the film advance thumb-wheel advances roughly one frame and the camera is ready to take its 17 picture (at the 1st dot on the reset counter). The camera will continue to take pictures until either the 35th picture is taken (16+19), or the ~long film load ends and the film sensing interlock no longer senses film. If less than 18-19 "extra" frames are taken, the last frame, will be exposed when the camera back is opened to remove the used film cassette.

Repair notes

The aluminum top cover, plastic viewfinder lenses (front and rear) and front label plate can be easily cleaned by removing the 2 small Phillips wood thread-type screws in the top of the camera. The top cover can be slid off with the camera in a normal upright position or tiled forward. The front plastic, front aluminum label plate will fall out of the top cover. The rear viewfinder lens slides upward from its slot, with the holding spring tab pointed upward and left. The black shutter button easily slides upward and off of the rectangular pin it sits on. The Isoflash Rapid C has some extra linkage to rotate the flash cube after each picture. The camera strap tab on the left is held in place by a simple slide in place copper piece.

The film counter indicator tab (silver aluminum) can be removed by removing the small circlip holding it in place. Underneath is a very fine coil spring to reset the film counter dial. The film counter dial can be lifted off of its post. Do not try to unscrew the brass post for the film counter it will damage the spring slot. To re-install the film counter, just place it back on the post, and get the spring in the slot. The counter can then be turned counterclockwise a full turn to pre-load the spring. The pointer and circlip can then be installed and the operation of the counter checked by rotating the counter to a number and opening the door to reset the film counter to "A".

Re-installing the top cover and viewfinder lenses is easy for the Iosflash Rpaid C. Just place the front plastic and aluminum name plate into the top cover and with the camera tilted forward slightly, slide the top cover on. The top cover slides down onto the camera body and tucked behind the lens, and the 2 screws installed.

The rear door latch is very simple, consisting of the black cover plate retained by 2 Phillips wood thread-type screws which covers the silver latch plate and a small spring. The 2 screws are removed, the black cover plate removed and the operation of the spring and latch plate can be seen. Reassembly is very easy.

The outer lens assembly is easily removed by removing the 2 Phillips machine thread-type screws which are located on the side of the lens 180 degrees apart. The lens assembly can then be pulled outward (forward) from the camera. The inner lens and outer lens surfaces can then be cleaned. Further cleaning would require the lens to be disassembled.

Once the lens assembly is removed from the camera, the fixed aperture and shutter plate can be seen. The shutter is cocked and when triggered swings to the right (looking at the camera) and hits or does not hit the shutter speed selector. There is a tiny ball bearing in the shutter speed selector that rides in a hole in the shutter speed selector and detents in the body of the camera. If this is lost the shutter speed selector lever can rotate to either position somewhat randomly.

With the shutter selector lever in the "shade/cloudy" position (clockwise), 2 small black slotted countersunk head wood-type screws can be seen, at the upper left and lower right of the shutter plate (looking at the camera). Removal of these 2 screws allows the shutter plate to be lifted slightly away from the camera. However, two wires for the flash circuit shutter switch are connected to the back of the shutter plate and prevent complete removal of the shutter plate from the camera body. These wires are riveted to the shutter plate and not easily removed. The yellow wire is soldered to a resistor, which connects to the + terminal of the battery. This can be seen if the brown insulator plate in the battery compartment is removed. The black wire from the shutter plate connects to one of two spring terminals for the flash cube.
NOTE: the brown insulator plate is held in place by the 2 deformed black tabs seen in the small slots in the brown plate. If it is removed, the deformed tabs are less effective at holding it in place and some glue may be needed to hold it in place.

Re-installing the shutter plate just requires that the shutter trip lever is in the correct slot in the silver shutter linkage on the left side of the shutter (looking at the camera). Then the 2 screws can be installed, carefully so they do not drop inside the camera. Check that the shutter selector lever operates without hitting the screw holding the shutter plate down. The front lens assembly can be slid onto the two tabs and the screw holes lined up. Install the 2 machine thread screws.