Corrupted pictures with chdkptp remote shooting for timelapse - Script Writing - CHDK Forum
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Corrupted pictures with chdkptp remote shooting for timelapse

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Offline jnixon

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Corrupted pictures with chdkptp remote shooting for timelapse
« on: 16 / January / 2017, 15:25:02 »
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Hello,

I'm a total newbie trying to use chdkptp to make a timelapse using remote shooting.  I have things working with the ptp CLI, but after a few minutes of shooting my pictures start looking corrupted.  They're mostly black and sort of look like they've been passed through an edge finding filter.  I'm not sure if this is a USB connection issue, a camera hardware issue, or something else.  Has anyone else seen anything like this using CHDK?  I've been using this command to start the time lapse. 

Code: [Select]
./chdkptp -c -e"rec" -e'lua while(get_flash_mode()<2) do click("right") end' -e"rs - quick=1000 -int=5"
Initially I used an interval of 5 seconds, then switched to 10 to see if the camera was over heating or having trouble due to the amount of pictures.  That didn't seem to help.  I also tried turning off the display using the following, but couldn't get that to work since the display switched on again as soon as the remote shooting started.

Code: [Select]
./chdkptp -c -e"rec" -e'lua while(get_flash_mode()<2) do click("right") end' -e"lua set_lcd_display(0)" -e"rs - quick=1000 -int=5"
I tried to attach a before and after shot of the image corruption.  I'm using a PowerShot SD700 IS.
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Offline reyalp

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Re: Corrupted pictures with chdkptp remote shooting for timelapse
« Reply #1 on: 16 / January / 2017, 16:32:18 »
I don't recall seeing anything like that reported before. It's odd to see a recognizable but corrupt image, most of the corruption I've seen is totally incorrect data.

It would be interesting to know if shooting with an intervalometer script on the camera without remote shoot produced the same results or not. You could use my fixedint script to do this:

http://chdk.wikia.com/wiki/Lua/Scripts:_Fixed_Exposure_Intervalometer

Settings I'd suggest
interval 50 for 5 second interval
Tv to something that gives you are recognizable image (Leave Tv=0 and use Tv + sec/10000 if you need shorter than 1/64)
Use raw off
Use cont mode unchecked

You should be able to leave the default values on the other

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I also tried turning off the display using the following, but couldn't get that to work since the display switched on again as soon as the remote shooting started.
This might be caused by having review enabled in the canon firmware. If it is enabled, it might be worth trying with it off.

You could also try using continuous mode rather than "quick" (-cont=... instead of -quick). You'll need to ensure continuous mode is enabled in the canon firmware, which needs to be done after every boot on older cameras.
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Offline srsa_4c

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Re: Corrupted pictures with chdkptp remote shooting for timelapse
« Reply #2 on: 16 / January / 2017, 17:56:43 »
I have seen pictures like that.
Quote from: jnixon on 16 / January / 2017, 15:25:02
a camera hardware issue
Failing (stuck open) mechanical shutter, combined with dark frame subtraction (due to long exposure time).
To prove, use the Canon controls to take a photo with exposure time greater than 1 second (CHDK is not even needed), without flash.
Also, regular (short exposure) images taken with the camera should show horizontal lines.
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Offline waterwingz

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Corrupted pictures with chdkptp remote shooting for timelapse
« Reply #3 on: 17 / January / 2017, 04:59:28 »
Quote from: reyalp on 16 / January / 2017, 16:32:18
It would be interesting to know if shooting with an intervalometer script on the camera without remote shoot produced the same results or not. You could use my fixedint script to do this:
Would the simple interval script installed by default with CHDK be adequate? If so, it would same a bit of effort downloading and it is trivial to configure.

Or were you thinking something capable of shooting faster is important?
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Offline reyalp

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Re: Corrupted pictures with chdkptp remote shooting for timelapse
« Reply #4 on: 17 / January / 2017, 12:41:28 »
Quote from: waterwingz on 17 / January / 2017, 04:59:28
Would the simple interval script installed by default with CHDK be adequate? If so, it would same a bit of effort downloading and it is trivial to configure.
Maybe? I suggested that script because it would use the same method as  "quick" in in the RS command.

@jnixon
Further to srsa_4c's suggestion, if you use the script, it would be a good idea to set the ISO and shutter speed to be the same as found in some of the corrupt images.
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Offline jnixon

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Re: Corrupted pictures with chdkptp remote shooting for timelapse
« Reply #5 on: 19 / January / 2017, 00:03:27 »
Thanks so much for the suggestions.  I've been working through them, but have limited time to work on this so it's taking a while. 

I haven't been able to play around with the scripts yet.

@reyalp
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This might be caused by having review enabled in the canon firmware. If it is enabled, it might be worth trying with it off.
Yes, this was the case.  I can disable the lcd display now. That actually seems to let me shoot for a longer period of time before the pictures start getting corrupted.

@srsa_4c
After experimenting for an hour or so I did start to notice horizontal lines on short exposure pictures.  This was not the case when I first started.  I assume this means my camera is busted.  Oddly, when I view the pictures in the initial review they look fine, but are then saved with the lines.
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