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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Another boring Noise Question...

Koray Birand

Koray Birand

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I have read tons of noise related questions within the last 10 years.. And here I am finding my self asking the same question..
I own a epic-w helium, have the latest firmware loaded.. Done my black shading manually.. I am sure the scene is well lid.. My skin tone is around 60IRE...
I always use my sekonic light meter and false color together... My compression is a bit to high 1:11 but thats the best i can get when shooting 75fps at 7K..
I need you guys hop in and tell me if this noise/grain/texture level is ok and let me know if I am being too picky..

Thanks...

Sample r3d files can be downloaded from :
https://we.tl/t-vOclIKeRe6
 
Kemalettin Sert said:
thats normal noise not anything to worry about it.Maybe you wanna go Helium 8K it does 75fps in 8K
Click to expand...
Well thats for sure.. but in the end it is the same sensor... They are not going to change the sensor. May be I will get better compression because of the processing power ..
 
PastedGraphic-5 by Björn Benckert, on Flickr


From looking at your histogram you could more than double up on light and that would only improve your image.


If not having more light and if shooting 75fps. I would rather shoot 360 deg shutter and gain some of that light, now your at 270 deg. But depends on the moment within the shot off course.

If you look at your histogram your exposure for her face lands at about 1/5 of peak which is not really ideal. That together with the high compression will not render optimal result.

But i dont see any crazy noise problems. But off course always depends what you are going to use the image for. If its "motion for stills" then the level of exposure gets really important.
 
Bjorn,

I am totally confused here... As i mentioned earlier, I am using a light meter and false color to make sure I expose the perfect light on my sensor..
According to your screen shot you are correct but this is what i see

with medium tone map and roll-off


and this is with none and very soft


All diffterent histograms.. and the screenshot you shared.. I could not simulate the same look from image-pipeline settings from preferences.
How should the image be exposed under which scenario... I am totally lost now.
 
Last edited:
Hi Koray, it looks like Björn was by-passing the 'Output Transform' settings to see a more 'RAW' type image. It's not essential, but go to, Edit>Preferences>Image Pipeline>IPP2 Monitoring and change Color Space to REDWideGamutRGB & GammaCurve to Log3G10 if you want to base your grade off a flatter image like that.

Here's an example similar to yours (but more crushed) using that method -



The important thing though, is to expose your mid-grey at or above the middle of the histogram if you want to avoid capturing noise there. That big spike of grey you've got at the lower end of the histogram should be up near where you've got the skin tones.

A rule of thumb is to expose to the right of the histogram, just below clipping, then darken the image back down in post.
 
Koray Birand said:
Bjorn,

I am totally confused here... As i mentioned earlier, I am using a light meter and false color to make sure I expose the perfect light on my sensor..
According to your screen shot you are correct but this is what i see

with medium tone map and roll-off


and this is with none and very soft


All diffterent histograms.. and the screenshot you shared.. I could not simulate the same look from image-pipeline settings from preferences.
How should the image be exposed under which scenario... I am totally lost now.
Click to expand...


Histograms show your lut. I always try to look at the "raw file" and see where the exposure lands. But as raw is always view trough a color transform of some sort the only thing that does not lie is the goalposts and stoplights.

So if you zoom in on her white robe and open up one stop at the time until the stoplight highlights. Then back down a stop. That would as I see it give you a higher exposure and less noise without losing any highlights.
 
Ok... So you both suggest me to take the priority to histogram rather then achive 60IRE (pink) on skin tones...
If i did not misunderstand... you are both telling me to rely on the histogram and expose the image as much as possible without clipping the highlights...
What about false color ?? should I not use it ?
 
Les Hillis said:
Hi Koray, it looks like Björn was by-passing the 'Output Transform' settings to see a more 'RAW' type image. It's not essential, but go to, Edit>Preferences>Image Pipeline>IPP2 Monitoring and change Color Space to REDWideGamutRGB & GammaCurve to Log3G10 if you want to base your grade off a flatter image like that.

Les Hillis...

I have updated to latest version and I do not have Log3G10 as a gama curve anymore

Click to expand...
 
choose hybrid log gamma and open your clip that you shared with us.Thats how you can get log3g10 with those setting unlesss you change your file browser clips settings to Show IPP2 Controls
bLWZLVy.png


yOsUq83.png
 
Hi Koray, go to Edit>Preferences>General, then check the box 'Show Advanced Controls'. That should make 'Log3G10' available on the 'Gamma Curve' drop-down list.

But, again, you don't necessarily have to grade your images from that starting point, it's just an option.

Edit -

I must admit I've never really used false-colour, but if it's adjustable, you might be able to assign different values to the same colours, or just use the same colour/values and figure out which ones will give you the increased exposure required for less noisy images.

It's just a case of calibrating your tools to suit the results you want.
 
Last edited:
Yes think I was in BT1886 to show something more "raw like". In my screen dump.


The roads to less noise:

Use as much of the sensor area as possible.
Compress as little as possible.
Use high exposure / low iso. Simply, post gain is whats makes noise visible. High iso accentiate the noise in the image / makes it more visible.


So to try another Terminology, bring your ISO down to 400 and give twice as much light. Now you are likely to have less than half the noise. Still your highlights are far from clipping. So nothing is lost.
 
Björn Benckert said:
Yes think I was in BT1886 to show something more "raw like". In my screen dump.


The roads to less noise:

Use as much of the sensor area as possible.
Compress as little as possible.
Use high exposure / low iso. Simply, post gain is whats makes noise visible. High iso accentiate the noise in the image / makes it more visible.


So to try another Terminology, bring your ISO down to 400 and give twice as much light. Now you are likely to have less than half the noise. Still your highlights are far from clipping. So nothing is lost.
Click to expand...

Björn, thank you for this valuable information.
I really appreciate it..
 
I was in the same ditch just a few weeks ago. We where shooting a female ninja talent. The idea was to shoot motion and stills at the same time. While on set I realized we had way to little light to shoot her moments somewhat sharp without too much falloff and also we needed short shutter times as she was doing flips and stuff. Simply needed something like 1/500 at a T9 or such... all in a very dark studio where we also need to lit the greenscren. Had to bring in more lights and even though we where short we could somewhat get it together for what we need.

Here is a JPG from that shoot. Where we simply exposed one stop under clip as I remember. Works well I think and all highlight info is there if I pull down iso then its also goes cleaner, but this looked good on big prints.

39767391103_4db1c2777c_k.jpg
[/url]Ninja_image by Björn Benckert, on Flickr[/IMG]
 
This might be the cleanest shot I have ever seen so far... I try not to shoot stills with RED.. As a photographer it is not practical for me when it is time to select shots...Because there will be thousands of images to go through..
But have I ever done it.. yes :)
 
You might what to try GIOscope or raw peaking (which only shows noise floor, 18% grey, and clip) instead of false colour or histogram, since GIO and raw view is based off the raw sensor data while false colour and histogram are not. In GIOscope, Chip 11 is supposed to be 18% grey.

Those forms of monitoring are ISO/LUT/gamma/colour independent and arguably the best place way to ensure you have optimal light.
 
Exposing correctly with Red is not super intuitive so I meet many that get noise that could have been avoided.
In this shot it seems like there is ISO 800 and the histogram is still empty in a larg part of the top, this will introduce noise for sure, if it was exposed maybe 2-3 stops brighter there would be much less noise.

The way I do is I always stay as close as I can to clipping (but no clipping!).
In general I put the ISO at 320 and then I change the aperture so that that there it will clip, then I make the aperture slightly smaller so I will not get clipping for small light changes.

Something worth trying could be to use the low light olpf. It is about 1/3 stop better than the default. The main benfits with the highligh olpf is that brighter colors will be more saturated and you do not get flare from sun-strong lights. Standard will get flare and the low light will also.

Hope that helps

Also remember blackshading only helps with static noise. Not with moving noise. Many think that black shade will help with the normal moving noise but this is not true.
Andreas
 
Part of the reason you have noise is also cropping in the sensor a little bit, which ends up making the noise more noticeable. It doesn't help also that the compression is 11:1, which accentuates it further. I totally understand though that there are reasons you need to jump down in resolution to achieve higher frame rates. Some organic noise is just a natural part of a CMOS image; without it the image might be too clean. You can alway apply Denoising (NeatVid, etc.), because none is done internally.
 
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