Bracketing series (for example for timelapse HDR)

vine

124
A560

Bracketing series (for example for timelapse HDR)

« on: 30 / April / 2008, 13:49:11 »

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What it does: Take a number of photos using the built-in bracketing in continuous mode function every X seconds for a set number of takes.
What it needs: get_jpg_count and/or get_raw_count included in Allbest's Builds
Tested and working on: A560 with Allbest build #50
Usage: Set cam to capture RAW, set cam to continuous mode, configure your bracketing mode (Extra Photo Operations > Bracketing in Continuous Mode), configure the three script parameters, start the script
The script:

Code: [Select]

@title Bracketing series by vine
@param a Number of shoots per take
@default a 3
@param b Seconds between takes
@default b 60
@param c Number of takes
@default c 10

for i=1 to c
get_raw_count x
y=x-a
press "shoot_half"
sleep 2000
press "shoot_full"
do
  get_raw_count z
until z=y
release "shoot_full"
release "shoot_half"
print "Take",i,"done"
sleep b*1000
next i
end

Known issues: In a series of about 15 test runs there were instances when during a take an additional photo was made (e.g. number of photos per take was set to three, but during one of ten takes it took four photos). It did not occur that less photos were taken.
Additional information: This is my first script and thus my first post in this subsection of the forums. I tried to make an as clean as possible post with all the relevant information, but since English is not my first language there might be some mistakes. The script works well for me, if you are using it and encounter any hiccups I'd love to get your feedback. Likewise if you scripting veterans see ways to improve my script please let me know so I may learn the finer arts of script writing.
Last, if you do not want to make RAW images, then you can use the slightly different script in my next post

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vine

124
A560

Re: Bracketing series (for example for timelapse HDR)

« Reply #1 on: 30 / April / 2008, 13:51:48 »

This is the modified version for JPG images instead of RAW:

Code: [Select]

@title Bracketing series by vine
@param a Number of shoots per take
@default a 3
@param b Seconds between takes
@default b 60
@param c Number of takes
@default c 10

for i=1 to c
get_jpg_count x
y=x-a
press "shoot_half"
sleep 2000
press "shoot_full"
do
  get_jpg_count z
until z=y
release "shoot_full"
release "shoot_half"
print "Take",i,"done"
sleep b*1000
next i
end

This is the same script as above, but the two instances of get_raw_count were replaced with get_jpg_count so the right number of pictures is taken per take when not working in RAW mode.

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avatorl

11

Re: Bracketing series (for example for timelapse HDR)

« Reply #2 on: 02 / May / 2008, 06:29:52 »

I think it'll be a great idea to combine your script with "Timelapse with variable shutter speed" script (c) Fbonomi

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fbonomi

469
A570IS SD1100/Ixus80

Re: Bracketing series (for example for timelapse HDR)

« Reply #3 on: 02 / May / 2008, 11:35:52 »

Quote from: avatorl on 02 / May / 2008, 06:29:52

I think it'll be a great idea to combine your script with "Timelapse with variable shutter speed" script (c) Fbonomi

The fact is, when you expose LOONG, bracketing for HDR purposes in not practical. If (for example), I expose 10", 20" and 40" seconds, the first and last shots will be VERY far away in time (such a sequence takes more than two minute total) and the scene will have changed (clouds, light conditions, etc)

Also, HDR parameters (I mean the parameters you use in HDR processing) should change from frame to frame, I am afraid: parameters that are Ok in the day would give bad results in the night.

I was thinking about this, but then I gave up (but, I must say, without really trying it)

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vine

124
A560

Re: Bracketing series (for example for timelapse HDR)

« Reply #4 on: 02 / May / 2008, 12:23:10 »

I'm afraid I have to agree with fbonomi here avatorl. HDR timelapse only works well with short exposure times (bright daylight, or well lit indoor scenes), so combining it with a script that is supposed to work in dark conditions is not really practical I fear.

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PhyrePhoX

2254
make RAW not WAR

Re: Bracketing series (for example for timelapse HDR)

« Reply #5 on: 02 / May / 2008, 12:28:44 »

also, the jpg or raw counter might not work that good, as it uses the canon counter, which is just an estimated guess on how many shots one can take. varying light means varying sizes of the jpegs which means jumpy counter imo.

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vine

124
A560

Re: Bracketing series (for example for timelapse HDR)

« Reply #6 on: 02 / May / 2008, 12:34:39 »

True, but since I couldn't find a prop for taken pictures on DICIG III and get_exp_count is not in my current chdk built afaik the get_raw/get_jpg method is the way I chose. It is fairly accurate (note my remarks under "Known issues:" in the original post)

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my photo map

my chdk page with tutorials, scripts and more

>> finally back from vacation (was a bit longer than intended) <<

PhyrePhoX

2254
make RAW not WAR

Re: Bracketing series (for example for timelapse HDR)

« Reply #7 on: 02 / May / 2008, 12:52:48 »

yeah i know, i was referring to the post that suggested using this for a timelapse.

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rawhead

18

Re: Bracketing series (for example for timelapse HDR)

« Reply #8 on: 02 / June / 2008, 22:32:29 »

Hmmm. Somehow, this script isn't working for me. I made sure all the settings are correct (I'm shooting in Tv mode using Tv Bracketing (value +/- 1), and when I start the script, setting it to take 3 shots per cycle, the cycle never ends, and it keeps on taking shots, going ever darker and brighter.

That is to say, it takes photos (I think) like:

0, -1, +1, -2, +2, -3, +3......

Until I manually quit the script.

Any ideas? I'm using an A620 with Allbest #50.

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Using Canon PowerShot A620 & A560

rawhead

18

Re: Bracketing series (for example for timelapse HDR)

« Reply #9 on: 02 / June / 2008, 22:48:36 »

OK, never mind, I guess that was because I was shooting in .jpg when the script was using get_raw_count.

However, once I got that figured out, I did notice immediately in my first try out, the script took more than the specified shots a few takes (4 instead of 3).

Do you know what causes this? Is it something in CHDK/Allbest build itself? Or, are there parameters that can be tweaked in the script to deal with it?

For me, this bug is critical because what I want to do is to use this script to generate HDR time lapse videos, where I will be taking thousands of photos, then batch generating HDR images. The batch processor takes X number of files at a time, meaning that if I'm taking a 3-shot bracketed images, I need there to be exactly 3 images per cycle for the batch script to work.

Any help would be appreciated.

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