seeking "definititive" HDR bracketing program - General Help and Assistance on using CHDK stable releases - CHDK Forum

seeking "definititive" HDR bracketing program

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Offline bugbear

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seeking "definititive" HDR bracketing program
« on: 03 / March / 2008, 11:23:15 »
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I've searched the wiki, and found "quite a lot" of exposure bracketing programs.

There is tremendous variation in what feature they need from CHDK (esp w.r.t props), and how they work.

IMHO the ones that use EV compensation are not usable. Any "proper" HDR bracketer should take (at most) one meter reading, and then work by altering shutter speed. Altering aperture is not good, since it would give different depth of field on the shots, altering the image itself.

The better scripts use focus lock, to avoid any focusing time after the first shot.

The better scripts put the camera's setting back to how they were at the start of the braketing run.

Scavenging...

This one does shutter speed bracketing (but no other good features)

UBASIC/Scripts/CanonA640: Shutter Bracketing - CHDK Wiki

This one exploits focus lock:

UBASIC/Scripts: an ultra fast HDR bracketing script for A6xx - CHDK Wiki

This one uses a half clock to get back to start point:

UBASIC/Scripts: EV bracketing with TV and AV commands - CHDK Wiki

I'm also fuzzy (but willing to learn) about the various CHDK builds that are mentioned; are these divergent builds mainly for the developers, or does each build have a sub user-group?

I'd have thought HDR would be quite a prime target for this group, but I can't find a good script for it.

Can anyone help me?

   BugBear (A630)

Re: seeking "definititive" HDR bracketing program
« Reply #1 on: 03 / March / 2008, 11:37:06 »
Deleted
« Last Edit: 22 / April / 2008, 13:16:36 by Barney Fife »
[acseven/admin commented out: please refrain from more direct offensive language to any user. FW complaints to me] I felt it imperative to withdraw my TOTAL participation. Nobody has my permission, nor the right, to reinstate MY posts. Make-do with my quoted text in others' replies only. Bye

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Offline bugbear

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Re: seeking "definititive" HDR bracketing program
« Reply #2 on: 03 / March / 2008, 11:52:52 »
Many of those scripts are now obsolete in many ways since the inception of the new Allbest Builds of CHDK, which has high-speed burst bracketing built into it (Tv, Av, ISO, & Focus). Recently a much more efficient and novel method of creating a set number of bracketed frames WITHOUT scripts was found, by using the camera's own internal Self-Timer > Custom setting.  (Otherwise you have to count them off yourself as you hold the shutter button in burst mode.)

See this thread "Discovery: Controlled Bracketing"

You are limited to 10 shots max using this method, but I don't see many situations where an HDR image would require more than that if you set your EV steps accordingly to the scene. 10 steps of 2EV each is almost 2/3rds to the full exposure range of most of these cameras.

Also see this thread, "Raw Average of pictures with different exposures" for what might be an even more convenient method of creating HDR images in the camera instead of using editing software .



Ah. Perhaps the wiki needs marking or purging; I didn't know I was looking at obselete facts.

The "raw Average of pictures with different exposures" isn't HDR, although it's similar.

I'm heading for the remarkable "enfuse" program, so I need "normal" HDR feed data.

edit: damn, my "perfect" script spec is lacking a feature; delayed start (allowing hands off use for stability)

   BugBear

Re: seeking "definititive" HDR bracketing program
« Reply #3 on: 03 / March / 2008, 12:00:10 »
Deleted
« Last Edit: 22 / April / 2008, 13:16:54 by Barney Fife »
[acseven/admin commented out: please refrain from more direct offensive language to any user. FW complaints to me] I felt it imperative to withdraw my TOTAL participation. Nobody has my permission, nor the right, to reinstate MY posts. Make-do with my quoted text in others' replies only. Bye


 

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