Isoflash-Rapid

Agfa IsoFlash-Rapid image by Dan Heil (Image rights)

The Isoflash Rapid is one of Agfa's series of squared-off, largely plastic, "Iso" cameras made for their easy-loading Rapid film system from the 1960s. It was designed to use individual single use flash bulbs rather than flash cubes as used with the IsoFlash-Rapid C.

Overview

The Agfa Isoflash Rapid is a simple fixed-focus Rapid models like the Iso-Rapid C and the Iso-Rapid I, and like those it gives 16 square exposures of 24×24 mm per roll of Rapid film. The lens is a ISINAR lens labeled "Made in Germany" with no focus adjustment or aperture adjustment. The shutter only has two settings, "sunny" and "shade/cloudy/flash". The fixed aperture can be seen through the front lens. There is no selenium light meter.

The shutter button is on the top of the camera. 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.

Like other Agfa Rapid cameras, this model uses two Rapid film cassettes, a new (full) film cassette which is placed into the right side of the camera back, and an empty film cassette, which is placed into the left side of the camera. The IsoFlash-Rapid does not have any mechanical sensors for the Rapid cassette ASA tab. The right side of the film area only has a metal spring to hold the new film cassette in place. The left side of the film area, which holds the empty receiving cassette, has a spring loaded forked shaped metal piece to match to the Rapid cassette ASA tab. However, this tab has no function other than to align (?) the cassette for receiving the film. The ASA tab on the Isoflash-Rapid camera does not care what ASA the empty receiving cassette is, so its not clear if anything is interlocked to the left spring fork.

The Isoflash-Rapid camera uses AG-1 type flashbulbs which insert into a socket on the the top left of the camera. A vertical thumb-wheel on the back of the camera, just to the left of the viewfinder raises and lowers the light weight metal reflector and moves a tab to hold the flash bulb in place. Between the view finder and the film advance thumb-wheel a flash guide is stenciled on, which gives recommended flash bulb types (AG-1B Blue, or AG-1 Clear) and recommended distance vs the Film type (AgfaPan, AgfaColor, AgfaChrome, or Agfapan). The battery (originally a mercury 6v type PX-23 battery) used to fire the flash, is located in the bottom of the camera.

Agfa Isoflash battery compartment and bottom cover image by Dan Heil (Image rights)

PX-23 Battery image by Dan Heil (Image rights)

IsoFlash-Rapid interior image by Dan Heil (Image rights)

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Operation

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 35mm film can be used to check the operation of the camera, even a short 5 frame piece of developed film.

In summary the operation of the camera has these 4 situations: Back door open, no film in the camera: Film advance thumb-wheel turns without stopping, shutter will not trigger. Back door closed, no film: Film advance thumb-wheel turns to advance one frame of film and stops, shutter will not trigger. 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. Back door closed, with film loaded, frame #1 shutter trigger -picture taken- (the last frame on the roll): 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. When the back door is open, film end tail is visible in the "empty" cassette on the left side of the camera.

The Agfa IsoFlash-Rapid requires that the shutter be triggered before the film advance thumb-wheel can advance film for each frame, including the beginning frames. When new film is loaded the film counter resets to "A". 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.

hacks, mods, modern use

Hand loading of the film presents risk to scratch or bend or kink the film. 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, cut 24" of bulk film using 2 descernable marks on the work surface. Then roll the film tightly into a roll and place it into the right side of a 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 frames of the film, then wind 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 (minus one) have been loaded, and the bull film safely wrapped, normal lighting 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 to allow easier loading (curved corner cut picture).

This can be an advantage to modern users of these cameras who are hand loading film into Rapid, SL (Schnell Laden)or DCS (reference to DCS in Rapid cameras) type cassettes. Any of these cassette types can be used for the new "loaded" film cassette which goes into the right side of the IsoFlash. An empty Rapid or SL cassette can then be used in the left side of the camera for the empty receiving cassette. The DCS type cassette is smaller than the Rapid or SL cassette and may require some cardboard shims to hold it properly in place to allow the film to be pulled out without jamming or damaging the sprocket holes.

Rapid Film had the emulsion type punched into the loose tail of the film to remind the photographer which kind had just been shot along with the word "End"

Rapid loads were standard perforated 35mm film, although thicker film. so today's photographer does not find it too daunting to reload empty Rapid cassettes in a darkroom; but the speed-index system does create the extra headache of locating (or modifying) cassettes for the correct tab length.

Thin film and longer rolls

Some modern 35mm films may have problems advancing the film in Rapid film type cameras, 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, since once the film counter reaches "0" in normal use, the film advances to the end without stopping. 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. The counter resets to "A" and the film advance thumbwheel 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 the film ends and the film sensing interlock no longer senses film. The last frame, may be overexposed when the camera back is opened to remove the used film cassette.

Links

• Multi-lingual manual at Mike Butkus' OrphanCameras.com
• Isomat Rapid at Sylvain Halgand's www.collection-appareils.fr (in French)