Time-lapse photography of clouds and other phenomena in the sky

Ricoh CA-1 cable switch

CA-1 cable switch is the Ricoh's optional USB-wired remote release for most of the recent Ricoh cameras. Officially, the CA-1 is compatible with GX8, GX100, GX200, GRD, GRD2, GRD3, CX1, CX2, CX3, CX4, and the GXR-system cameras, however works even with R3, R4, R5, R6, R7, R8 and R10 cameras. The principle of the camera control is shown above right (image source here). Half-pressing the shutter-release button of the CA-1 sends the first 30 ms pulse, instructing the camera to measure the exposure (AE) and focus (AF). If the camera dial is set to M mode and/or focus mode is set to infinity, the AE and/or AF are ignored. Next, full-pressing the shutter-release button (150 ms pulse) forces the camera to take and save the image. Releasing the button sends the 3x30 ms pulse sequence, finishing the previous action.

Understanding the scheme above is crucial for using the CA-1 in continuous mode (CONT=ON) of the camera. When in this mode, full-pressing the CA-1 shutter-release button starts the sequence, releasing it stops the sequence (sending the 3x30 ms pulse "off" sequence). If you want to take long series, you have to hold the shutter-release button pressed all the time, to avoid the 3x30 ms pulse sequence being sent to the camera. One possibility is a rubber band holding the shutter-release button pressed instead of your finger. If you reach the 999 images limit of the continuous mode and want to continue instantly with a new series, you have to release the button and press it again. Other possibility how to achieve this more efficiently, without the rubber band, is the following trick. When you start the sequence, hold the button pressed, and without releasing it switch the power button (ON-OFF) of the CA-1 to the position OFF. This way you will avoid CA-1 sending the camera the 3x30 ms pulse terminating the sequence, and the camera will keep shooting the sequence until reaching the 999 shots limit. If you want to terminate the sequence before reaching the 999 shots limit, you just have to half-press and release the shutter-release button on the camera body, or switch the CA-1 on and do the same with its shutter-release button - in both cases releasing one of the two buttons will send the 3x30 ms pulse and stop the sequence. If you want to take a longer series (above the 999 images), just switch the CA-1 on before reaching the 999 shots limit, and after the sequence stops (reaching the 999 limit), just repeat the trick from above...

The continuous mode can be used as a faster alternative to the interval mode; the intervals are somewhere between 0.65 to 0.8 s, depending on the shooting conditions. Fast card is essential for this - slower cards may result into irregular intervals, or even disable longer series. Also, slower cards may result into "freezing" of the camera if you start the second series right after the first one, after reaching the 999 shots limit. Also, don't forget that in this mode the camera locks the AE, AF and WB, using the values of the first image of the series. There seems to be a certain problem with the exposure - usually the camera slightly overexposes the whole series as compared to the first image of the series (by about 1.5 stop); this doesn't seem to be a GX100-specific problem, it was reported also with some other camera models. You can find several examples of "timelapse movies" taken in the continuous mode in my 2009, 2010 and 2010-USA galleries. 

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