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Bracketing Intervalometer

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Bracketing Intervalometer
« on: 22 / May / 2008, 23:30:19 »
I am new to CHDK and this forum.  I've found this to be absolutely fascinating and am trying to learn what I can.

I have a particular use that I am having trouble understanding.  I recently flew a high altitude balloon to 61,000' and had onboard a Canon A570is runing an intervalometer program taking a photo every 30 seconds.  It worked very nicely.  However, the balloon did, of course, get above the cloud deck and in to the bright sunlight for a good portion of the flight.  As such the camera over-exposed the cloud deck quite badly.  I believe the Canon attempts to average the field of view for a good exposure but in a HAB flight there is far too much contrast from the upper edge of the dark of space to the blue atmosphere to the extreme white of the clouds.  What I need, I believe, is a bracketed intervalometer to drop an F-stop or two when above the cloud deck but still maintain the average when below.  The HAB flights typically take about 2.5 hours up and down and taking a photo every 30 seconds seems to get those terrific 'money shots' at altitude.  Can anyone help me find a script and understand a bit more on a good place to start with settings?

These are photos from 61,000' on my recent flight:


« Last Edit: 22 / May / 2008, 23:32:17 by BHPete »


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Re: Bracketing Intervalometer
« Reply #1 on: 23 / May / 2008, 03:42:17 »
Bracketing series (for example for timelapse HDR) takes a set number of photos with different exposures (or other bracketing settings) every X seconds. That way you can choose the one with the best exposure or even merge them to a HDR image if the balloon is steady enough.
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