Night-time time-lapse - page 8 - Completed and Working Scripts - CHDK Forum

Night-time time-lapse

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Re: Night-time time-lapse
« Reply #70 on: 16 / June / 2009, 16:05:24 »
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This is great stuff!
I can't wait to try it tonight!

I've been doing sunsets for the last couple of weeks (just a basic shooter, without stretching the exposure limits)
I tried the Sunset4.bas script last night that was posted to the wiki, and then started digging in the forums today.. I'm going to run  sunsetF16 as soon as I get a chance..

I noticed that it loaded a data table at one point during initialization, (A/CHDK/DATA/sunsetF16.tbl)
does this have important stuff in it, or will it do ok without?

On the other side of the exposure coin,
I was wondering how hard it would be to push into the high speed shutter settings
when the sun is actually directly visible to the camera (as it's moving down toward
the horizon)

I've seen a couple high speed shots of the direct sun that made it a nice orange disc.
On a clear day, watching the sun go down without it being heavily over exposed and
then transitioning into a nighttime sky would be particularly nice!

You guys have done some great work!
All of the Lua libraries are very well coded, I need to dig into them further,
and maybe I can make a contribution...

Thanks!
-chuck

Re: Night-time time-lapse
« Reply #71 on: 19 / June / 2009, 19:23:30 »
590
S90

Re: Night-time time-lapse
« Reply #72 on: 24 / June / 2009, 11:55:26 »
Hello
the sunsetF16 works better...
Why can't we use photoshop histogramm to appreciate brightness? What is different with script values? (because on photoshop it's from 0 to 255)
thx
590
S90

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Offline fbonomi

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Re: Night-time time-lapse
« Reply #73 on: 27 / June / 2009, 02:52:13 »
Why can't we use photoshop histogramm to appreciate brightness? What is different with script values? (because on photoshop it's from 0 to 255)

Yes, we could use the 0-255 range instead of the 0-1023 range, it's just a matter of multplying them by 4.

but BEWARE: there is a HUGE difference between the histogram read by the script and the histogramas seen in photoshop, as the script reads the RA image and photoshop sees the conveterted image.

For example, the 0 in photoshop might not correspond to the 0 in the RAW, the 255 in photoshop might not correspond to the 1023 in RAW. Plus, the two are not linearly correlated!!


Re: Night-time time-lapse
« Reply #74 on: 08 / July / 2009, 16:40:01 »
thx for details of histogram!

Today, another bug happens. The script runs, but the parameters (exposure time and iso) don't change. It is always 1/2000eme sec and ISO 100....pictures are all black...I try to change script parameters, but nothing changes. The script ran very well since weeks. I don't do special modifications since the last use of the script, which was good...I don't know!

there's "deleteuntilmbfree"... :

log:
--- Log opened at 2009/07/08 22:21:45 ---
platform: a590 100e
version: CHDK 0.9.8-776 built on Jun 12 2009 08:53:35
Sunset F1
Parameters (user given in paranthesis)
picsAnHour:   120
max_tv:   -420   (10 s)
default_sv:   419   (ISO 100)
max_sv:   707   (ISO 800)
histo_under_start:   0   (0)
histo_under_end:   23   (23)
histo_under_limit:   30
histo_under_weight:   30
histo_over_start:   160   (160)
histo_over_end:   1023   (1023)
histo_over_limit:   4
histo_over_weight:   0
histo_median_value:   16   (80)
histo_median_weight:   50
focus_to_inf:   1
jpg_quality:   -1   (no change)
jpg_resolution:   -1   (no change)
startupdelay:   0 min

##   Time   Frame   bv   night_correct   day_correct   dusk_factor   correct   current_tv   smoothed_tv   shoot_tv   shoot_sv   Topt   Tccd   Tbat
disk.deleteUntilMbFree - Mb Min:20Mb Target40disk.deleteUntilMbFree - get free spacedisk.deleteUntilMbFree - Exitutil.sleepUntilNextPeriodOfAnHour - start
util.sleepUntilNextPeriodOfAnHour - end
00 - -287, 273 = smartShoot(newFileName(),2781,419,65535)
Histo Measure: 0 0 0
Correct: 0 0 -2500
Correction: 3125
01 - night_correct:3125
02 - -141=-287-273+419
Measured: -287 273, Calculated: -141
03 - -2922=((-141-2781) * 100 ) / 100
04 - -14610=-14610*5
05 - -140 = -287 - 273+
06 - -140>=96
08 - -140<=96 - 576
10 - 409=((96--140)*1000)/576
11 - -7357=-14610+((3125--14610)*409)/1000
12 - 2634=2634 + (-7357/50)
13 - 2634=2634
14 - 2634=2634
15 - 419=419
16 - 2634<-420
19 - 419 > 707
##   2009/07/08 22:22:04   1   -287   3125   -14610   409   -7357   2634   2634   2634   419   30   37   28
22 - 419
23 - 2634
disk.deleteUntilMbFree - Mb Min:20Mb Target40disk.deleteUntilMbFree - get free spacedisk.deleteUntilMbFree - Exitutil.sleepUntilNextPeriodOfAnHour - start

If there's a known solution for that, it would be perfect... if not, i will format and install again everything...
thx




590
S90

Re: Night-time time-lapse
« Reply #75 on: 20 / July / 2009, 20:07:27 »
  current_tv=current_tv + (correct/50)

'Proper' smoothing adds some of the old and the new, so given a smoothing factor 'alpha', you would use: 'value = value * (1 - alpha) + new * alpha' which results in an exponential filter which should approach the final value and not oscillate if 'alpha' factor is correctly chosen.  Start with alpha = 0.33 then modify alpha to speed or slow the resulting filtered value.

I've not tried this yet as I have a different scenario I want to try, for timelapse to auto-skip night-time with longer sampling 'til start of new day.  Unless I can teach the cam to do startrails by night, dawn/dusk and cloud movie by day :)
« Last Edit: 20 / July / 2009, 20:11:17 by bugsplatter »

Re: Night-time time-lapse
« Reply #76 on: 23 / July / 2010, 15:38:48 »
[I posted originally to ask about this but I just tried it and this works]

I wanted to use a max shutter speed of about 1/10 s, but the script only allows a range of 1 to 65 seconds. This is important for my use, as I'll be using it on a roadtrip for multiple days and if I'm driving, the images cannot have a long exposure to look right. It also has the benefit of preserving the time between each frame.

I changed

Quote
max_tv=sec_to_tv96(check_range(b,1,65))

to

Quote
max_tv=b

and set b to a Tv96 value that I want
« Last Edit: 23 / July / 2010, 16:15:36 by munk_e »

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Offline fbonomi

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Re: Night-time time-lapse
« Reply #77 on: 23 / July / 2010, 16:40:14 »

I wanted to use a max shutter speed of about 1/10 s, but the script only allows a range of 1 to 65


In this case, why don't you just use a simple intervalometer?





Re: Night-time time-lapse
« Reply #78 on: 23 / July / 2010, 21:43:21 »

I wanted to use a max shutter speed of about 1/10 s, but the script only allows a range of 1 to 65


In this case, why don't you just use a simple intervalometer?



I wanted to have exposures through day and night transitions, and with all I've read here I suspected it wouldn't work as day breaks. Your post had me studying a bit more and I see I just needed to learn how to configure the settings correctly for my project. I did a few simple tests with yass v2 and it does indeed get the exposure correct when there's more light after darkness. With so much to learn, I guess I got ahead of myself and didn't see the simpler approach, thanks!

Re: Night-time time-lapse
« Reply #79 on: 27 / September / 2011, 21:16:51 »
Wow wow wow, what is LUA? How do i install this beautyful feature in my Canon 350D?

 

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