Manual shutter speed for timelapse - Script Writing - CHDK Forum
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Manual shutter speed for timelapse

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Offline squadgazzz

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Manual shutter speed for timelapse
« on: 25 / April / 2015, 15:04:59 »
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Hello!

I've searched for few scripts, but didn't find what I want.
Is there any script where I can manually set the shutter speed with shutter interval?
Something like 3 sec shutter speed and 3 sec shutter interval.

I have ixus 117 hs.

thank you
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Offline waterwingz

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Re: Manual shutter speed for timelapse
« Reply #1 on: 25 / April / 2015, 15:31:23 »
Something like this ?  (Cobbled together quickly from several other scripts).

Code: [Select]
--[[ Manual Shooting Intervalometer
@title Manual v1.0
@chdk_version 1.3
@param     a Interval (sec)
 @default  a 15
 @range    a 2 30000
@param     t Tv exposure (secs)
 @default  t 25
 @range    t 1 3600
@param     e ISO
  @default e 2
  @values  e 80 100 200 400 800 1250 1600 3200 6400
@param     x ND filter
  @default x 0
  @values  x Out In
--]]

    -- switch to record mode if necessary
    if ( get_mode() == false ) then
        sleep(1000)
        set_record(1)
        while ( get_mode() == false) do
          sleep(100)
        end
    end

    -- turn seconds into tv96 values and get sv and av setpoints
    tv96 =seconds_to_tv96(t,1)
    local sv_table = { 381, 411, 507, 603, 699, 761, 795, 891, 987 }
    sv96 = sv_table[e+1]

repeat
    start = get_tick_count()
    set_sv96(sv96)
    set_tv96_direct(tv96)
    if(x == 1) then                      -- ND filter requested ?
        set_nd_filter(1)                 -- activate the ND filter
    else
        set_nd_filter(2)                 -- deactiveate the ND filter
    end
    press("shoot_half")                  -- half shoot and wait for auto exposure
    repeat
    sleep(10)
    until get_shooting() == true
     press("shoot_full")                  -- take the photo
    sleep(50)
    release("shoot_full_only")
    sleep(50)
    release("shoot_half")
    repeat
    sleep(20)
    until get_shooting() ~= true
    sleep(a*1000 - (get_tick_count() - start))
until ( false )
Note : you can't just set the shutter speed - you need to override the ISO and ND filter too.  If your camera had an adjustable aperture (it doesn't) then you would need to override that too.
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Ported :   A1200    SD940   G10    Powershot N    G16
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Offline squadgazzz

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Re: Manual shutter speed for timelapse
« Reply #2 on: 04 / May / 2015, 02:14:02 »
oh, thank you!
What are ND parameters doing? (in\out)
can you also add 'turn off the screen' param please?
and what happening with diaphragm? it's still in auto?
should I use exposure meter for this?
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Offline waterwingz

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Re: Manual shutter speed for timelapse
« Reply #3 on: 04 / May / 2015, 08:50:22 »
Quote from: squadgazzz on 04 / May / 2015, 02:14:02
What are ND parameters doing? (in\out)
Your cameras has a built-in Neutral Density filter.  When you shoot, you need to decide if you want it in (in the light path) or out (out of the light path).  If the script does not set this,  the camera will make its own decision and you might not get the exposure you were expecting.

Quote
can you also add 'turn off the screen' param please?
Upgraded script attached.   I suppose you are going to want a "lock focus at infinity" option next?  :P

Quote
and what happening with diaphragm? it's still in auto?
Your camera does not have an adjustable diaphragm (also called iris or aperture).  It's fixed at the maximum lens opening.  That opening size changes with zoom position but is otherwise not adjustable.   And that's why you have a neutral density filter to adjust exposure - see my comments above.

Quote
should I use exposure meter for this?
I actually have no idea what your application for this is.  You asked for a shutter speed of three seconds so I gave you a range of  one to 3600 second on a hunch.  What kind of exposure meter are you thinking about using and for what shooting situation.
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Ported :   A1200    SD940   G10    Powershot N    G16
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