Suggest a script for zero noise technique

markanini

37

Re: Suggest a script for zero noise technique

« Reply #10 on: 06 / December / 2015, 21:01:53 »

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After the initial shot it takes a underexposed shot, then an overexposed shot. I'd prefer and overexposed shot after the initial shot.

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Flickr: markanini's Photostream

waterwingz

12139

Re: Suggest a script for zero noise technique

« Reply #11 on: 06 / December / 2015, 22:15:08 »

Quote from: markanini on 06 / December / 2015, 21:01:53

After the initial shot it takes a underexposed shot, then an overexposed shot. I'd prefer an overexposed shot after the initial shot.

Change

Code: [Select]

tv96val=tv-n*s/2
for i=1, n, 1 do
print("step=", i, "tv96=", tv96val)
fastshoot(av,sv,tv96val)
tv96val = tv96val+s
end

to

Code: [Select]

tv96val=tv+n*s/2
for i=1, n, 1 do
print("step=", i, "tv96=", tv96val)
fastshoot(av,sv,tv96val)
tv96val = tv96val-s
end

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Ported : A1200 SD940 G10 Powershot N G16

markanini

37

Re: Suggest a script for zero noise technique

« Reply #12 on: 06 / December / 2015, 22:38:59 »

Hmm. With positive 'tV step size' the initial shot is underexposed and the second is normal. With negative 'tV step size' both are the same exposure. To clarify I want one normal exposure followed by one overexposed exposure.

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Flickr: markanini's Photostream

waterwingz

12139

Re: Suggest a script for zero noise technique

« Reply #13 on: 06 / December / 2015, 22:44:06 »

Quote from: markanini on 06 / December / 2015, 22:38:59

Hmm. With positive 'tV step size' the initial shot is underexposed and the second is normal. With negative 'tV step size' both are the same exposure. To clarify I want one normal exposure followed by one overexposed exposure.

Code: [Select]

fastshoot(av,sv,tv96val)
tv96val=tv+s
fastshoot(av,sv,tv96val)

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Ported : A1200 SD940 G10 Powershot N G16

ShahJahan

30
King Of The World

Re: Suggest a script for zero noise technique

« Reply #14 on: 12 / January / 2016, 14:12:11 »

Quote from: markanini on 01 / December / 2015, 19:41:36

I want to bracket two exposures, One normal followed by one that is +4 f-stops by reducing the shutter speed. If possible with minimal delay between the two.

More about the zero noise technique: http://www.guillermoluijk.com/article/nonoise/index_en.htm

My camera is Canon s90.

You can do that without a script! In CHDK, find Auto Bracketing > Tv bracket > 4 Stops
Then set timer to 0 Sec, 3 Pics
This will shoot 3 pics in +4 0 -4
If you think 4 is too strong a stop, then you can set the timer to 0 Sec 5 Pics with 2 Stops and it will shoot +4 +2 0 -2 -4

Another way to remove noise (without HDR effect)
Use the interval.lua script (thanks waterwingz for showing me this script) and take 'n' number of Pics.
Then in photoshop, create a smart object and median stack all the images.

Technique learned from this place (it really works wonders, WITHOUT altering lighting conditions, like HDR does): http://petapixel.com/2013/05/29/a-look-at-reducing-noise-in-photographs-using-median-blending/

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The name ShahJahan comes from Persian, where Shah means King and Jahan means World,
so the name ShahJahan in its literal sense means King of the World.