Author Topic: Low-noise in low-key with RAW: ETTR + PP (brightness down)???  (Read 837 times)

adrjork

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Low-noise in low-key with RAW: ETTR + PP (brightness down)???
« on: November 01, 2018, 06:13:12 PM »
Hi everyone,

I'm trying to make a sort of low-key video shot: in a dark room there's a woman watching at the window that should be the only light source.
If I make the shot as I described, directly with the "final" low-brightness I desire, the histogram is very low, and my shot is full of noise.
I tried to raise up the ISO, but the few highlights (the woman's face) starts clipping.
A solution could be using a soft light in the room in order to reduce the difference between the highlights and the shadows. In this way my shot should be less noisy, but it will loose the "final" low-brightness I want. Anyway I should be able to correct this in PP (lowering the brightness-under-a-certain-value to "bring back" the shadows to their darkness).

Do you think this is a good method, or it's better shooting in the desired "final" light + using a de-noise in PP?

Thanks in advance.

whitelight

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Re: Low-noise in low-key with RAW: ETTR + PP (brightness down)???
« Reply #1 on: November 01, 2018, 11:50:56 PM »
I think the best solution if the camera is not moving would be to use a green screen behind the woman and then replace it with the background shot as dark as you want it.

adrjork

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Re: Low-noise in low-key with RAW: ETTR + PP (brightness down)???
« Reply #2 on: November 02, 2018, 12:27:42 AM »
Whitelight, thanks for your reply.
Anyway, the camera is not moving, but the woman interacts with many objects in the room. I can't do green screen here.

IDA_ML

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Re: Low-noise in low-key with RAW: ETTR + PP (brightness down)???
« Reply #3 on: November 02, 2018, 12:57:21 PM »
Then, your only  option is Dual ISO.  It does a hell of a job with killing noise and artefacts!  Give it a try.

adrjork

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Re: Low-noise in low-key with RAW: ETTR + PP (brightness down)???
« Reply #4 on: November 02, 2018, 04:11:02 PM »
Hi IDA_ML, thanks for your reply.
Yes, DUAL-ISO is an option, and it's surely an improvement in dynamic range, but... 720p...
Anyway, don't you think that the soft light in the room should work like DUAL-ISO? (It should work like a sort of light equalizer, no?)

IDA_ML

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Re: Low-noise in low-key with RAW: ETTR + PP (brightness down)???
« Reply #5 on: November 02, 2018, 10:48:42 PM »
Dual ISO has nothing to do with the light or its softness.  It just allows you to boost the signal to noise ratio in the dark areas of the image which allows lower noise in that areas and higher overall dynamic range, especially when used with ETTR.

adrjork

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Re: Low-noise in low-key with RAW: ETTR + PP (brightness down)???
« Reply #6 on: November 02, 2018, 11:32:07 PM »
Well, please correct me if I'm wrong: with Dual ISO we have one ISO for bright areas (usually a low ISO) mixed to a second ISO for dark areas (usually an higher ISO). This sounds to me like a sort of brightness-equalization of different areas of an image. Dual ISO makes this sort of equalization gaining the sensor for the secondary higher ISO. Instead (in my example with an ambient light in the room) I'm trying to do the same equalization simply gaining the ambient light itself (making dark areas less dark...)
Is that all wrong?

Levas

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Re: Low-noise in low-key with RAW: ETTR + PP (brightness down)???
« Reply #7 on: November 03, 2018, 05:52:40 PM »
A solution could be using a soft light in the room in order to reduce the difference between the highlights and the shadows. In this way my shot should be less noisy, but it will loose the "final" low-brightness I want. Anyway I should be able to correct this in PP (lowering the brightness-under-a-certain-value to "bring back" the shadows to their darkness).

Do you think this is a good method, or it's better shooting in the desired "final" light + using a de-noise in PP?

Thanks in advance.

For the least amount of noise, it’s always better to shoot the most bright image(without highlight clipping) and bring exposure down in post proces.
If shootin  natural, you can also crush or cut the shadows to bring down noise.
Search for video editing cut and lift shadows or crush shadows  ;D

adrjork

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Re: Low-noise in low-key with RAW: ETTR + PP (brightness down)???
« Reply #8 on: November 04, 2018, 12:58:20 AM »
Thanks Levas for the reply.