Noise issues. w BMPCC 6K

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Jonathan West

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Noise issues. w BMPCC 6K

PostSat Aug 31, 2019 12:41 am

Hi.. I shoot for a living. Just rec'd new 6k cam for my personal work. Testing reveals a lot of noise.. varied my ISO, exposure subject matter. Even when the histogram is filled across the spectrum, the mid tones to the shadows start to get noisy at around ISO 640. Very visible at 3200. At the. top end, ISO 25600, the. image is unuseable... unless I pour on the NR.

I won't go into detail about test shots etc. It's just noisy.
Any comments?

I"m not sending it back to B&H... what's the policy here at Blackmagic? I'd like to have someone take a look
at it. I live close to the Burbank offices but not sure where the. repair addresses may be.

Thanks
Jonathan West
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rick.lang

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Re: Noise issues. w BMPCC 6K

PostMon Sep 16, 2019 1:49 pm

Contact BMD Support for your region as described on their webpage; their site is on California but it’s not a drop-in service; you’ll need to mail the camera to them after they give you an RMA. But first, they’ll need to see samples of your frames that are too noisy while the histogram apparently had good coverage.

BMD will want to assess if your camera is faulty or behaving normally.


When you are shooting, have you used False Colour? If you do that, there will be portions of your frame that may be blue or purple. That should be the only area that might be too noisy when shooting at ISO 640. Blue should be usable in post, purple means lost details and you can’t salvage it simply; often you pull down those purple areas to crush the noise.

ISO 3200 naturally will be noisier than ISO 400. All other ISO settings use the two available gain ranges. Exposing for ISO 200 or 1250 might give you better results.

You could post samples here too.


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Rick Lang
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Stephen Fitzgerald

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Re: Noise issues. w BMPCC 6K

PostMon Sep 16, 2019 5:07 pm

Interested to know your setup, past camera experience with noise and if this isn’t normal. As always if you could provide visual examples, ideally RAW footage so we can download.

All that said, I second the when looking at false color don’t have anything in purple or blue...when I first got the UM4.6k I was an everyday shooter with the Sony cinema camera range, so coming over to the UM I would constantly complain about noise. Now I know how to use my scopes specifically for the UMP, not saying this is your bad, just wanted to make sure it’s not a low light/no light issue. I usually make sure my exposure is good even 1 stop under.

I live in Burbank and when I talked with BMD at cinegear they said they may be able to provide some small limited hardware support here, obviously nothing like Canon or Arri.
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Robert Niessner

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Re: Noise issues. w BMPCC 6K

PostMon Sep 16, 2019 5:15 pm

Jonathan West wrote:Hi.. I shoot for a living. Just rec'd new 6k cam for my personal work. Testing reveals a lot of noise.. varied my ISO, exposure subject matter. Even when the histogram is filled across the spectrum, the mid tones to the shadows start to get noisy at around ISO 640. Very visible at 3200. At the. top end, ISO 25600, the. image is unuseable... unless I pour on the NR.

I won't go into detail about test shots etc. It's just noisy.
Any comments?


Don't expect the same ironed out noise and detail free images as like with a Sony Alpha / FS7 / Canon C100 or the like. They all apply heavy in-camera de-noising onto the footage.

As always - please provide details about your light levels, setup and post unaltered source footage for others to assess.
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Jonathan West

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Re: Noise issues. w BMPCC 6K

PostWed Sep 25, 2019 4:50 pm

I want to thank you all for your very helpful replies. I didn't want to be an alarmist or react too quickly. So I decided to do much more shooting with the camera to get a better feel for where the ideal exposure levels are. So far, I've discovered that I need to allow for more exposure to lessen or eliminate the noise I referred to. Even though the image on the screen (BM RAW Film 6k to the other BM LUTS) seemed to have a lighter than desired look, the histogram and the false colors showed much more information in the darker parts of the frame and could still hold the highlight detail. So I needed to create an "on set" LUT that would keep that exposure and could be used to give a better representation to me (and the director) of what the scene should look like ie. darker shadows and mid tones on the monitor(s). Something I could rely on. Then, in DaVinci Resolve, I use that LUT as reference only. So far, the noise "problem" has almost disappeared. Because I can edit with the RAW footage, I can make color grading adjustments throughout the editing process. It's quite wonderful. Thank you ALL again for your replies. I will continue this thread if need be.
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vivoices

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Re: Noise issues. w BMPCC 6K

PostWed Sep 25, 2019 6:03 pm

I am having a similar issue. The image on screen is too bright and washed out when I expose to the right. Even the built in LUT does not compensate enough.

Jonathan, what custom LUT are you using?
Udo Jansen

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rick.lang

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Re: Noise issues. w BMPCC 6K

PostWed Sep 25, 2019 6:45 pm

Have you tried exposing more for the scene and not forcing ETTR? If you’re shooting ProRes, do not ETTR. but even raw exposed for the scene with perhaps a stop shifted to the right will give you a manageable view on the monitor.

Or in Resolve, pull that bright image down several stops and make a custom LUT that you copy to your camera and apply to the monitor view if needed.


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vivoices

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Re: Noise issues. w BMPCC 6K

PostWed Sep 25, 2019 6:55 pm

rick.lang wrote:Or in Resolve, pull that bright image down several stops and make a custom LUT that you copy to your camera and apply to the monitor view if needed.
I will try a custom LUT from Resolve, thanks Rick.
I shoot in BRAW only.
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Thompsonrh

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Re: Noise issues. w BMPCC 6K

PostSat Jan 11, 2020 3:12 pm

I'm not a video expert but am learning a lot about the most recent technologies and how as a professional photographer you have to think differently. The importance of understanding the subject scene, in terms of the amount of shadow and highlights in the scene and setting ISO accordingly (somewhat the same as Ansel Adams Zone system). See Page 50 in the manual. If you landed on ISO 640 as part of the best setup for the scene then the question to ask, is this a mainly dark scene or mainly bright scene? If it is mainly dark, then a better setting might be ISO 1250 because your dynamic range in the shadows goes from 7 stops (ISO 640) to 8.5 stops (ISO 1250) on the 6K model. If the scene is mainly bright, then ISO 640 might be better although ISO 1000 would give more dynamic range in the bright areas than 640, but ISO 1250 would be a bad choice in this case of more bright tones. This is all because of the dual ISO capability. Seems to me its like another dimension in the setup process. I appreciate that dynamic range and digital noise are not the same thing but with the better dynamic range, there's less curve adjustments needed in the deep shadows. Having said all this, I do agree with the original Post, I am surprised at the amount of noise in my 4K at native ISO 3200. Although exposed well and adjustments made for input and output color space, I definitely need to apply NR.
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John Paines

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Re: Noise issues. w BMPCC 6K

PostSat Jan 11, 2020 3:36 pm

Thompsonrh wrote:I'm not a video expert but am learning a lot about the most recent technologies and how as a professional photographer you have to think differently. The importance of understanding the subject scene, in terms of the amount of shadow and highlights in the scene and setting ISO accordingly (somewhat the same as Ansel Adams Zone system). See Page 50 in the manual. If you landed on ISO 640 as part of the best setup for the scene then the question to ask, is this a mainly dark scene or mainly bright scene? If it is mainly dark, then a better setting might be ISO 1250 because your dynamic range in the shadows goes from 7 stops (ISO 640) to 8.5 stops (ISO 1250) on the 6K model. If the scene is mainly bright, then ISO 640 might be better although ISO 1000 would give more dynamic range in the bright areas than 640, but ISO 1250 would be a bad choice in this case of more bright tones. This is all because of the dual ISO capability. Seems to me its like another dimension in the setup process. I appreciate that dynamic range and digital noise are not the same thing but with the better dynamic range, there's less curve adjustments needed in the deep shadows. Having said all this, I do agree with the original Post, I am surprised at the amount of noise in my 4K at native ISO 3200. Although exposed well and adjustments made for input and output color space, I definitely need to apply NR.


Applying a film analogy to ISO as its implemented on BMD cameras, as you're doing above, is only going to get you into trouble. It doesn't help that most of the posts above don't distinguish between braw and Prores, or offer a word about how the shots were actually exposed.

And the infamous Facebook group hysteria, promoted by John Hess and others, that shooting at ISO 1000 magically offers more "highlight headroom" simply ignores the fact that you can only get to 1000 by upping the digital gain (noise!), and stopping down the lens by the same amount you're boosting the signal. Big surprise! You can just easily shoot the scene at a lower ISO, meter for iso 1000, and raise levels in post, and get the same or better result. If you ask me, that blasted chart is the source of endless and pointless disputation over ISO.

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