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proposal - script shooting hooks

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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #20 on: 25 / December / 2014, 22:59:08 »
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A successful, if boring example. At the start exposure is driven by under exposure protection, pushing the metered area almost 1 stop over neutral but not quite far enough to test that limit. By about the middle the sky darkens enough for the metered area to be neutral. Looking at the log I think there might be a bug in the transition, but it didn't affect the results much in this case.

Total exposure change is about 1.8 stops. Individual exposure changes are almost always ~2 APEX96 units at a time.

http://youtu.be/hivtoQU7xJQ

Aforementioned glitches
http://youtu.be/RUMe06EQFd8
Don't forget what the H stands for.

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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #21 on: 26 / December / 2014, 14:01:11 »
Updated script attached. This should fix the bug with the transition from over/under protection and regular metering. I also switched the sign of d_ev, so now positive is more exposure (longer shutter speed, higher ISO) and added indicators for the over / under protection in the draw function.

A readme with full details is included in the zip.
Don't forget what the H stands for.

Re: proposal - script shooting hooks
« Reply #22 on: 26 / December / 2014, 14:25:18 »
On the road right now.  Would you mind posting an S100 101a build for me?   I'll probably have a bit of time to play with it if so.

TIA
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #23 on: 26 / December / 2014, 15:24:56 »
On the road right now.  Would you mind posting an S100 101a build for me?   I'll probably have a bit of time to play with it if so.
The C code is in the trunk autobuild.

edit:
If for some reason you can download here an not the autobuild, I'd be happy to post one. You also need rawoplib.lua, which is included in the trunk CHDK/LUALIB

Also, as noted earlier I haven't added Av or ND support. Since the script keeps half press down, it should stick with whatever the camera used for the first shot, and exposure calculations should not be affected.

I'd suggest using a larger, sparser meter than the script default, something like 1200 step 5 maybe
« Last Edit: 26 / December / 2014, 15:57:12 by reyalp »
Don't forget what the H stands for.


Re: proposal - script shooting hooks
« Reply #24 on: 26 / December / 2014, 16:39:13 »
I've got 3843 with me. Is that current enough? Otherwise I can update.
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #25 on: 26 / December / 2014, 16:47:37 »
I've got 3843 with me. Is that current enough? Otherwise I can update.
Need to update, C code went in at 3848. Suggest 3859 or later.
Don't forget what the H stands for.

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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #26 on: 26 / December / 2014, 21:06:13 »
Another boring test. Where are my clouds  >:(

http://youtu.be/IGG8NOj89m4
Don't forget what the H stands for.

Re: proposal - script shooting hooks
« Reply #27 on: 26 / December / 2014, 22:57:53 »
I think you need to get some skis & a toboggan and head up to Spenser's Butte?
« Last Edit: 26 / December / 2014, 23:00:47 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16


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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #28 on: 27 / December / 2014, 15:36:46 »
I think you need to get some skis & a toboggan and head up to Spenser's Butte?
Yeah, I should totally bill the customer for travel to appropriate testing locations... oh, right :P

Meanwhile... Clouds!
http://youtu.be/NzLj45IcL_0

This worked pretty well, still didn't challenge the metering code much. It looks like the value I consider over-exposed (currently hard coded 1000-1023) is a bit too high. The over expose % stayed <= 1 even though the brightest clouds were blown out in the Canon jpeg. OTOH, in a scene like this letting them be blown out may be the better choice (the sun is just out of frame on the right).
Don't forget what the H stands for.

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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #29 on: 28 / December / 2014, 14:41:37 »
In trunk build 3861, I added rawop.ev96_to_raw which takes an APEX96-ish value (0 = neutral) and converts it to a raw value. Among other things, this lets you get shot_histogram ranges in terms of EV. Additionally, I changed the definition of raw_neutral exposed to Lua to include blacklevel, so it represents an actual raw value.

Updated script attached. Trunk build 3862 or later is required.

This update fixes a nasty flipped sign bug in under exp handling, plus the following changes:

Improved transition from under exposure limiting.

Exposure ranges considered over or under exposed are now user selected, in terms of exposure stops. Note they are specified in slightly different ways:
Over exposure is fractions of a stop below white-level (so 1 = 1 stop below white level, 96 = 1/96th of stop). On my cameras there are ~2.5 stops between neutral and white level.

Under exposure is stops below neutral. This is more useful than specifying over black level, since on a log scale there are several stops over black level that have negligible significance. On my cameras you tend to start getting (actual) black level pixels ~5 stops below neutral (shooting a uniform neutral subject.)

Shutdown options now split into individual booleans, and now includes and option to shut down when SD space is low.

I'm not really satisfied with the way the exposure logic is put together at the moment. I need a general way to smoothly transition between the different regimes. The current code has special cases to reduce flapping at various transitions, but doesn't catch them all and is hard to verify. That said, it does a pretty good job some of the time :)

Here's and example hitting the over exposure limits
http://youtu.be/QiddcAOax8o

edit:
12/30 attached zip containing correct files  :-X
« Last Edit: 30 / December / 2014, 15:06:39 by reyalp »
Don't forget what the H stands for.

 

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