Author Topic: Extrem ISO Noise  (Read 1136 times)

Nzyer

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Extrem ISO Noise
« on: March 16, 2017, 07:28:16 PM »
I am using the Canon 70D with the 18-55mm IS STM Canon Standart Lense.

I installed Magic Lantern, everything is working well so far except one little / big problem...

When I am filming, I try to use good settings like always ISO 100 and if its too dark, I use bright movie lights and all that stuff. The Live-View Window always looks good and I going to record it, but the RAW result looks extremly more dark than the Live-View Window. It's sometimes not too bad so I try to convert the RAW file with the Magic Lantern Raw Converter to DNG files, make it a clip in Black Magic Resolve and put a Colorgrade on it. But as soon I try to make it a little bit more brighter, everything starts to get hard ISO noise and it looks like recorded with iso 12.000 with only a candle as light setup, even when I recorded it with big lights or even in the brightes sun. What do I do wrong? Is it me? The settings? The Lense? Or is it not possible for the camera sensor?

I hope someone can help me.


Levas

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Re: Extrem ISO Noise
« Reply #1 on: March 17, 2017, 11:15:06 AM »
Probably the settings.
Quote
like always ISO 100
Sounds like the problem, good exposed iso 100 gives almost no noise, but underexposed iso 100 gives much noise.
Try to enable raw histogram in magic lantern menu and see how it looks ? (if you're unsure how histogram works, try googling it).
You want the histogram to touch the right side, then you're exposure is good.
It's better to go higher in iso to move the histogram to touch it the rights side, so use iso 200, 400, 800 maybe even 1600 if nessecarry.
It's always better, noisewise, to use higher iso to get proper exposure, then using low iso and have underexposure.


Kharak

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Re: Extrem ISO Noise
« Reply #2 on: March 17, 2017, 02:27:49 PM »
Have you tried opening the DNG's in any other software than Resolve?

I find resolve unusable with CinemaDNG's from Magic Lantern, because its simply too bad at debayering. So I go the long route of transcoding in ACR via Cinelog-C to a more intermediate Codec and then import everything in to Resolve.

So try ACR and see if you still have the same noise issues. ISO 100 with a light setup should be crystal clean. I personally don't shoot anything higher than 200 ISO because you can just push the exposure afterwards. The Canon Raw is almost ISO less anyways..

And ofcourse, try different converters raw2cdng, mlvmystic or if you are on Mac then you have lots of options. To my knowledge Magic Lantern RAW Converter is pretty outdated.
once you go raw you never go back

Nzyer

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Re: Extrem ISO Noise
« Reply #3 on: March 17, 2017, 06:39:31 PM »
Thanks so far, I will try my luck :)

Roberto Mena

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Re: Extrem ISO Noise
« Reply #4 on: March 17, 2017, 06:48:19 PM »
Adding to what Levas said, this technique is called ETTR, Exposing To The Right and using ML's ETTR tool (RAW Histogram) makes using this technique much easier. You use the ETTR tool by pointing your camera on the subject or area you want to measure exposure and then adjust your iris (a variable ND filter is also really useful for this when you do not have de-clicked iris cinematic lenses) until the ETTR tool reads EV 0.0, now you have a correct balanced exposure, but now you open up the iris (or variable ND filter) by one f stop so it now reads -1.0 EV, you are now over exposing the image by one 1 f stop. Now in post you re-adjust the exposure by lowering it and or using curves to adjust. This works for my 7D so well that I currently shot a significant part of my short film at 1600 ISO because I had a crappy light kit that I borrowed and I did not get noise but rather a really clean picture and my 7D is notorious for bad noise at 1600 ISO.

Audionut

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Re: Extrem ISO Noise
« Reply #5 on: March 20, 2017, 05:22:49 AM »
The Live-View Window always looks good and I going to record it, but the RAW result looks extremly more dark than the Live-View Window.

I can never remember which setting this is, but I think it's ExpSim that causes this issue.

But if you use RAW based exposure feedback, you'll get expected results.  (and yes, I do need to update the image links).