Isoflash-Rapid

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

[url=https://flic.kr/p/28QxbEm][img]https://farm2.staticflickr.com/1835/43212466064_4bb0d233e6_k.jpg[/img][/url][url=https://flic.kr/p/28QxbEm]20180803_223603[/url] by [url=https://www.flickr.com/photos/153904022@N06/]Dan Heil[/url], on Flickr

Preliminary, in work. borrowed from Isomat page

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 vs the IsoFlash-Rapid C which was designed to use flash cubes.

The Isoflash Rapid is one of Agfa's simple fixed-focus Rapid models like the Iso-Rapid I and like those, it gives 16 square exposures of 24×24 mm per roll. 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 Agfa IsoRapid camera uses AG1B type flash bulbs which insert into a socket on the the top left of the camera. A vertical thumbwheel 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 advance thumbwheel 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 (6v type xxx) used to fire the flash is located in the bottom of the camera.

Normal operation

The camera has two interlocks for 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 thumbwheel 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 developed 5 frame piece.

In summary the operation of the camera has these 4 situations: Back door open, no film in the camera: Film advance thumbwheel turns without stopping, shutter will not trigger. Back door closed, no film: Film advance thumbwheel 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 thumbwheel will continue to advance the film without stopping until the film has been pushed past the film sensing interlock into the receiving cassette, with only the film end tail remaining visible when the rear door is opened.

The Agfa IsoFlash Rapid requires that the shutter be triggered before the film advance thumbwheel can advance film for each frame. When new film is loaded the film counter resets to "A". The film advance thumbwheel 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 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.

Speed indexing

(Image rights)

The Agfa IsoFlash-Rapid does not have any mechanical sensors for the Rapid cassette ASA tab. The right side of the film area only has a L shaped 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, the camera does not care what ASA the empty receiving cassette is, so its not clear if anything is interlocked to the left spring fork.

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.

Loading film

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).

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)