Yet Another Sunset Script (yass) v4.5 - page 9 - LUA Scripting - CHDK Forum

Yet Another Sunset Script (yass) v4.5

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Re: Yet Another Sunset Script (yass) v4.5
« Reply #80 on: 15 / September / 2014, 15:12:49 »
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Crash happens in LEDDrv.c task LEDCon

Try changing the
Code: [Select]
@param y Status LED
@default y 2
to something else  (Off, 0, or 1 ).  It's possible the LED code is not implemented correctly for the A470.
« Last Edit: 15 / September / 2014, 15:15:12 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Yet Another Sunset Script (yass) v4.5
« Reply #81 on: 15 / September / 2014, 15:15:08 »
Now I install version 1.3 and I start the cript. It seems that it works.
I will test it.
Thanks

Re: Yet Another Sunset Script (yass) v4.2
« Reply #82 on: 01 / November / 2014, 08:42:24 »
Meanwhile, here's a little script that will actually measure the correct offset value (in f-stops or apex96 units) of your camera's ND filter.  Useful if you want to adjust the script.

I got the following results:

Code: [Select]
Shooting conditions 96 288 320 opt. temp.
Indoor, bright light coming from
the window - 1 2-3-4-5 38
At the window, looking outside,
aimed at very bright subjects
(80% bright buildings, 20% bright, blue sky) 2 - 1 36
At the window, looking outside,
aimed at very bright subjects
(50% bright buildings, 50% bright, blue sky) 1-2-3-4 -          - 36


This reads like: in the first row, shoot #1 resulted 288, shoots #2, 3...5 resulted 320

Considering that the luminance (I guess it is the correct term for that) of the bright part of sunsets or sunrises in my city are more a less like the conditions in the third row, I presume I should set nd96 variable in yass4 to 96, correct?

Just fyi, I live in a tropical city where the shift between night and day lasts no longer than an hour, thus, a place where the luminance changes abruptly, when compared to the luminance change in cities farther from the equator. That's what leads me to think that I need to adjust yass4.
Canon A3100IS - 100d
CHDK a3100-100d-1.2.0-3643-full_ALPHA

Re: Yet Another Sunset Script (yass) v4.2
« Reply #83 on: 01 / November / 2014, 10:35:39 »
This reads like: in the first row, shoot #1 resulted 288, shoots #2, 3...5 resulted 320
Considering that the luminance (I guess it is the correct term for that) of the bright part of sunsets or sunrises in my city are more a less like the conditions in the third row, I presume I should set nd96 variable in yass4 to 96, correct?
These results are a little bit confusing.  It's very unlikely that your ND filter decreases the exposure setting by only one f-stop (which is what the 96 value means).   

More likely, the brightness of the scene outside your window is overloading the camera during the test (just my guess here).   

I'd suggest using the 320 value (which is slightly more than 3 stops).

If you'd like to test this, I've attached a little script that takes two shots  - one with the ND filter in and the other with the ND filter out - and adjusts the exposure based on the # of f-stops defined in the script parameter.   If you have the f-stop value right,  the exposure of the two resulting images should match.

Update : attachment removed - updated version in later post
« Last Edit: 01 / November / 2014, 13:54:36 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16


Re: Yet Another Sunset Script (yass) v4.2
« Reply #84 on: 01 / November / 2014, 12:41:37 »

If you'd like to test this, I've attached a little script that takes two shots  - one with the ND filter in and the other with the ND filter out - and adjusts the exposure based on the # of f-stops defined in the script parameter.   If you have the f-stop value right,  the exposure of the two resulting images should match.

Indoors, I could get two exposure matching pictures with f-stop = 3

Aiming the camera out of the window, on perhaps even brighter conditions than those I described above, with the same f-stop of 3, I got two completely blown pictures, with the last one almost blank. (repeated the test, same results)

Still aiming out of the window, I decreased the f-stop to 1: the first picture is blown, the second is ok. (repeated the test, same results)
Canon A3100IS - 100d
CHDK a3100-100d-1.2.0-3643-full_ALPHA

Re: Yet Another Sunset Script (yass) v4.2
« Reply #85 on: 01 / November / 2014, 12:49:22 »
Indoors, I could get two exposure matching pictures with f-stop = 3
Which confirms that your ND filter gives the equivalent of a 3 f-stop change

Quote
Aiming the camera out of the window, on perhaps even brighter conditions than those I described above, with the same f-stop of 3, I got two completely blown pictures, with the last one almost blank. (repeated the test, same results) Still aiming out of the window, I decreased the f-stop to 1: the first picture is blown, the second is ok. (repeated the test, same results)
So something in the camera setup is not allowing it to either increase the shutter speed enough and/or decrease the ISO setting.   The script tries to set both and reports the results.  I've updated the script to also create a log file - please rerun the test a couple of times (with f-stop=3) and  post the results (  from A/CHDK/LOGS/LOG_0002.TXT )

Update : doh! ... when you point the camera outside, it tries to automatically engage the ND filter.  The script is kinda brain dead and does not notice that.  Which throws off all the exposure calculations.  Updated script attached.
« Last Edit: 01 / November / 2014, 13:53:59 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

Re: Yet Another Sunset Script (yass) v4.5
« Reply #86 on: 01 / November / 2014, 14:10:40 »
Thumbs up!

I ran the script three times, pointing the camera outside, still plenty of light, and the exposure of both photos match in all rounds.

So, as you have already said, I should set up yass4 with dn96= 320, which is the same as f-stop=3, right?

Fyi, the script output is

Code: [Select]
ND Test : avmode= 1
 ND in tv=791 av=565 sv=371 bv=999 exp=58
 ND out tv=1079 av=565 sv=371 bv=1000 exp=59
...done
*** FINISHED ***
ND Test : avmode= 1
 ND in tv=791 av=565 sv=371 bv=997 exp=57
 ND out tv=1079 av=565 sv=371 bv=998 exp=57
...done
*** FINISHED ***
ND Test : avmode= 1
 ND in tv=791 av=565 sv=371 bv=999 exp=57
 ND out tv=1079 av=565 sv=371 bv=1000 exp=58
...done
*** FINISHED ***
Canon A3100IS - 100d
CHDK a3100-100d-1.2.0-3643-full_ALPHA

Re: Yet Another Sunset Script (yass) v4.5
« Reply #87 on: 01 / November / 2014, 14:16:10 »
So, as you have already said, I should set up yass4 with dn96= 320, which is the same as f-stop=3, right?
To convert f-stops to APEX96 values just multiply by 96.   So 320 = 3 1/3 stops.   And 3 stops = 288.

Close enough.

Ported :   A1200    SD940   G10    Powershot N    G16


Re: Yet Another Sunset Script (yass) v4.5
« Reply #88 on: 01 / November / 2014, 15:14:40 »
Thanks!

I'm still confused about some yass4 parameters.

What should drive the choice of Tv Normal Limit and Exposure Ramp Rate? Is it related to the brightest scene that will happen during sunset or sunrise? Is it related to how long the sunset/sunrise will last?

For example, given that the sunrise brightest scene will be a very bright day and that the sunrise duration will last no longer than an hour (from dark night to bright daylight), does it mean that I will have to increase Tv Normal Limit and set Exposure Ramp Rate to Fast or VFast?
Canon A3100IS - 100d
CHDK a3100-100d-1.2.0-3643-full_ALPHA

Re: Yet Another Sunset Script (yass) v4.5
« Reply #89 on: 01 / November / 2014, 17:00:53 »
I'm still confused about some yass4 parameters.
To be candid,  I inherited most of the logic from this script from the earlier yass2.bas script,  which in turn came out of the yass.bas script and the sunset4.bas script before that.  Most of that stuff is from back in 2008.   I converted to Lua to make the script readable and converted the user parameter to work in real worlds units rather than apex96 values.

All if which means there are no really solid answer to your question.  It's more a question of tweaking things and trying it until you get what you like.

Quote
What should drive the choice of Tv Normal Limit and Exposure Ramp Rate? Is it related to the brightest scene that will happen during sunset or sunrise? Is it related to how long the sunset/sunrise will last?
The Tv normal limit sets the point at which the script starts filtering.  Above that value it just shoots normally.  Below the value it tries to smooth out exposure changes.  The Exposure Ramp Rate sets how fast & how big the script make individual exposure changes.  The origins of the logic might be back in some really old forum posts but I think what it is trying to do is keep the exposure from jumping quickly as the sun goes in & out of clouds (for example) while it sets.

FWIW,  lapser has a whole series of scripts and CHDK mods he did to try and get this right.  He tended to post across many threads on a somewhat random basis so its a little hard to follow what he did and (so far) it still requires a customize version of CHDK to replicate everything he accomplished. The core of his work is here :  Shot Histogram Request
Ported :   A1200    SD940   G10    Powershot N    G16

 

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