In-Camera HDR - Feature Requests - CHDK Forum  

In-Camera HDR

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In-Camera HDR
« on: 30 / July / 2012, 01:58:17 »
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HDR manually is easy enough.

However it occurred to me that CHDK could likely do that in-camera - and do it faster and more accurately with some kind of script that brackets based on scene exposure (selecting exposures just below clipping and just above blackout).

I'm sure different kinds of tone-mapping and curves could be incorporated as selections within the script and we'd have good in-camera HDR.

By having a script automate it, the shots would be taken much faster than by the operator and the results could be seen while in the field as opposed to having to wait to see them after processing.

C.

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Offline reyalp

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Re: In-Camera HDR
« Reply #1 on: 30 / July / 2012, 02:21:16 »
However it occurred to me that CHDK could likely do that in-camera - and do it faster and more accurately with some kind of script that brackets based on scene exposure (selecting exposures just below clipping and just above blackout).
CHDK can do bracketing, without a script http://chdk.wikia.com/wiki/CHDK_User_Manual#Bracketing_in_continuous_mode

This is done as fast as the camera can make the exposures.

You might be able to make a script that intelligently figured out the required bracket range, but doing a stop or two in each direction should be sufficient in most cases.
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I'm sure different kinds of tone-mapping and curves could be incorporated as selections within the script and we'd have good in-camera HDR.
This cannot be done in script, and would be quite difficult to do on camera at all. The camera is not a convenient place to do image processing, because the CPU is slow, memory is very limited, and standard software libraries are not available.

If the image processing side of Digic were better understood, that might change things.
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By having a script automate it, the shots would be taken much faster than by the operator and the results could be seen while in the field as opposed to having to wait to see them after processing.
CHDK cannot make the camera shoot faster than continuous mode.
Don't forget what the H stands for.

Re: In-Camera HDR
« Reply #2 on: 31 / July / 2012, 02:36:20 »
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CHDK can do bracketing, without a script http://chdk.wikia.com/wiki/CHDK_User_Manual#Bracketing_in_continuous_mode

This is done as fast as the camera can make the exposures.

Yes, I know that. Its not what I was referring to. I don't use the CHDK bracketing because it simply takes a preset range of exposures. To do HDR (proper HDR) the best way is to manually set exposure and manually take the photos (which is what I do). That way I get the proper range of exposure rather than an automated but inaccurate (or unnecessary) range.

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You might be able to make a script that intelligently figured out the required bracket range, but doing a stop or two in each direction should be sufficient in most cases.

This is exactly what I meant - though a stop or two is rarely enough. After many many tries I've found that most landscapes require a lot more than 1 or two stops. Most daylight landscapes require between 7 and 12 stops in my experience. I've been doing that manually and getting some good results, but a script as you described above would accurately automate the procedure making proper HDR a lot faster.

I can forgo the in-camera processing. That is easily done on a computer. But the automatic  selection of the full dynamic range of scene  along with automated shooting of it is what would be most helpful - in terms of speed (important because clouds can move rather quickly) and accuracy (nothing worse than excellently framed scene found not having enough DR with clipping and shadow blocking ruining the image).

I'm not able to make any script, let alone one that would intelligently figure out the required bracket range. How about you or anyone else familiar with scripts and CHDK?

Thank you
C.
« Last Edit: 31 / July / 2012, 02:40:14 by cantain »

 

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