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LCD turnoff during timelapse with an A470

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LCD turnoff during timelapse with an A470
« on: 11 / April / 2010, 11:31:31 »

I'm attempting to do a 4 hour time lapse with a canon A470 utilizing the CHDK and an intervalometer script. So far I've been successful in running the script and have started to do some tests to determine the number of images I can collect within 1 battery life. Obviously, the LCD screen will need to be shut off.

I've attempted to use all of the scripts on this web site, and none have been successful at turning off the LCD screen. Even if I set the firmware menu to "turn off LCD @ 10 seconds," it turns back on with the next picture's preview. When attempting to turn off the preview function, the script fails to continue and the camera has to be rebooted.

So - I've seen a couple of solutions on this board, including attaching an AV cable, as well as modifying the code to turn the LCD off with each shot. I tried using the AV cable, which works, but the camera was only able to run for 1.5 hours (661 images at 10 sec intervals) before batteries were drained. I'm assuming that while the cable is plugged in, extra battery power is drained.

Someone suggested using the "set_backlight" command to shut the LCD off without using the cable, but Im unsure how to modify the script's code to use it. That brings me to my question:

**Can someone modify either the simple or ultimate intervalometer script so that it will automatically shut the LCD off after taking the first image?** - any advice greatly appreciated!



Offline fudgey

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Re: LCD turnoff during timelapse with an A470
« Reply #1 on: 11 / April / 2010, 17:16:42 »
If you only get 1.5 hours with the AV plug method, there's no way you'll get 4 hours with disp off... maybe 2.5 to 3 hours. You need external power.

Anyway, the key to minimizing power consumption between shots is to disable the sensor, not just the LCD or backlight. There are two ways to do that: either work in Canon's display off mode or in PLAY mode. Note that you can't use manual focus with display off (and in play mode MF gets disabled at lens retract, and before retract it probably consumes almost as much power as the backlight, which you of course should to disable if you decide to wait in PLAY mode).

To minimize power consumption during shots, you want to disable the LCD or at least its backlight during shooting as well. This can be done with an AV plug or repeated use of the set_backlight command in the script.

Try this:
1) Disable review (I always keep review disabled btw...when I want to see the photo I took, I keep the shutter depressed until I'm done).
2) Set up a regular timelapse script (one that doesn't fiddle with the display button).
3) In REC mode, press DISP button to turn off the display (or if your camera doesn't have one, do whatever you normally do to disable the LCD for still shooting, regardless of CHDK).
4) Plug in the AV cable.
5) Press ALT, then fully press shutter to start the script.

Personally I don't like doing timelapses this way because it puts more stress on mechanical parts of the camera (at least focus and iris) -- any sound emitted means something's moving.

Crash with review disabled sounds weird and should be a matter of the a470 porting thread, I suppose.


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