G12 Manual Focus C1 problem-help

Started Mar 3, 2011 | Discussions thread
tribomber New Member • Posts: 6
Re: G12 Manual Focus when LCD turned off

After considerable investigation and testing, I believe I have found the solution (within CHDK) to this issue.
First off, what I was looking for was a way to have my G12 take a very long series of time-lapse snaps from indoors while unattended.  For this, I set it up with and AC adapter, UPS battery backup, and a CHDK intervalomter.  I chose to go with the Low Drift one detailed here:
I wanted to stay in manual focus and I wanted the display to go off between shots (to reduce power draw and to preserve the life of the LCD).  Per everything I read, including emails with Canon, this was not doable...the G12, and most Canon Powershots I guess, by design will return to AF as soon as the display is turned off.
The solution I found here (much thanks to CHDK forum member "lapser!"):
It is the use of the set_backlight(0) command within CHDK.  I guess this blacks out the display without actually turning it "off" for camera logic purposes.  I modified the main loop within the intervalomter script as follows:
  while (get_tick_count-j-(i*t))<0
    sleep 10000        -- added this line to give me 10 secs to see the display before it goes out
    set_backlight(0)   -- added this line to black out the display
    sleep (t/100 - 10000)  -- added "- 10000" to this line to maintain the overall sleep interval
until i=a

So far, this is working perfectly!

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