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"Blue noise" in the shadows. How do you shoot "black"??

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Matt Williams

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I'm currently shooting with the Scarlet and have been running into blue specks of noise in the shadows. After reading around I've come to the conclusion that I am obviously "under-exposing" the shadows. My question is, why does that create noise? Isn't the point of a shadow that it is under-exposed and darker than your subject? How do you film someone against a background that is supposed to be in shadow without getting this blue noise?

Camera information:

400 ISO
48 fps
1/96 sec shutter
1:7 compression ratio
3K
Zeiss Super speed glass (typical stops ranging from 1.2-4.5)

You'll notice in the R3D snapshot I've here: http://www.mediafire.com/file/iwqhq2mm2kag1zz/A002_C033_0224ED_001.0000320F.R3D
That the blacks on this particular shot are very concentrated with a specifically "blue" noise. How do I shoot a shot like this without getting that (and without having to crush the blacks in post)?
 
you'll probably just have to crush the blacks down in post. Also remember that Red does no noise reduction in camera so plugins like Neat Video are a must for any Red users arsenal. I would also make sure and do a black shade when the camera gets up to temperature.
 
Gotcha...What exactly do you mean when you say to do a black shade when the camera "gets up to temperature"? Thank you very much for your time!
 
look good now? (BEFORE)
ccd1.jpg




AFTER (wooooo)

ccd.jpg
 
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Matt,

While waiting, pull-out or download your camera manual and read up on the set up section. There, it describes how to perform a black calibration.

Because any sensor creates noise at different temp levels, you turn on the camera and allow it to 'heat up,' if you will, for a moment. Then, the software performs a check and attempts to (in a general sense) wipe out the noise level.

Because the Red is allowing you full control, you will need to shoot a stop or so over what's normal so you achieve some "details in the shadows," and then, you remove them. Sounds crazy? Welcome to the crazy world of professionals! :D This is the kind of thing we want. It allows someone to create a look because the world is wide open to them. It's the total opposite of the consumer camera idea.

Hope that helps. Now, go play!

-Glen
 
Thanks! That helps a lot! :) I'll go do that!

And Justin, did you just do that tweak in Redcine-X? Could you possibly tell me which changes you made??
 
Matt Williams said:
Thanks! That helps a lot! :) I'll go do that!

And Justin, did you just do that tweak in Redcine-X? Could you possibly tell me which changes you made??
Click to expand...

Yep, al in RCX..

I adjusted the shadow and contrast, a bit, upped your ISO to 800, brought your KELVIN to aroun 2700? don't really remember, got rid of a little RED and GREEN, and added a bit of brightness..

I think its great if you have the time to BLACK BALANCE often on your shoot, but most of the time its just impossible.. I have my AC do it before he even rolls the cart out of the truck.. usually you can make things work in post as long as you expose properly.. If you under expose you will have trouble when you try to get the blacks "black".. You exposed nicely, so it was easy to bring the black to black.. I have no idea why your TINT was so wacky though! Keep an eye on that stuff..


RAW IS A FUCKING AMAZING TOOL, but you need to make sure you expose properly and you will 99% of the time be fine..
 
Thank you so much man! That relieves me a lot. I completely forgot to black balance (haven't shot red for over a year), and I knew something had to be wrong, because it didn't seem right to be getting that much noise. MOST appreciated! :)
 
Matt Williams said:
Thank you so much man! That relieves me a lot. I completely forgot to black balance (haven't shot red for over a year), and I knew something had to be wrong, because it didn't seem right to be getting that much noise. MOST appreciated! :)
Click to expand...

Even when you black balance you still might see a bit of noise in the blacks.. Sometimes its nice actually.. Just know as long as you light your scene well you can get rid of it.. (also there is software too)
 
That's a relief...What de-noiser would you recommend for a FCP editor (He has color, and Red Giant)? I'm a DP but typically don't cut or grade the footage I shoot.
 
Justin Marx said:
Yep, al in RCX..

I adjusted the shadow and contrast, a bit, upped your ISO to 800, brought your KELVIN to aroun 2700? don't really remember, got rid of a little RED and GREEN, and added a bit of brightness..

I think its great if you have the time to BLACK BALANCE often on your shoot, but most of the time its just impossible.. I have my AC do it before he even rolls the cart out of the truck.. usually you can make things work in post as long as you expose properly.. If you under expose you will have trouble when you try to get the blacks "black".. You exposed nicely, so it was easy to bring the black to black.. I have no idea why your TINT was so wacky though! Keep an eye on that stuff..


RAW IS A FUCKING AMAZING TOOL, but you need to make sure you expose properly and you will 99% of the time be fine..
Click to expand...

Justin would you recommend over exposing in all situations. I work primarily in the documentary world and I'm worried I'll lose too much detail in the highlights (mainly outdoor shooting) if I'm overexposing for shadows (although there shouldn't be too many if I'm outside). Just curious.

Thanks,
Jacob
 
J Taylor said:
Justin would you recommend over exposing in all situations. I work primarily in the documentary world and I'm worried I'll lose too much detail in the highlights (mainly outdoor shooting) if I'm overexposing for shadows (although there shouldn't be too many if I'm outside). Just curious.

Thanks,
Jacob
Click to expand...

Nooooo, don't over expose.. Do your best to expose properly for your scene.. If you have a black BG, just make sure you don't "under expose" your scene, as noise will be harder to deal with..
 
Matt Williams said:
My question is, why does that create noise?
Click to expand...

I can't tell you scientifically why it happens, but imaging chips have always been noisy in the blue channel.

If I were to make a serious inquiry I might start by considering the fact that in the blue portion of the spectrum, silicon reflects almost as much light energy as it absorbs. It's actually closer to 60/40, but blue is more susceptible than any other part of the visible spectrum. Red on the other hand is reflected the least @30%. Plotted on a graph the curve is fairly flat across the spectrum, with a sharp rise in reflectivity in the blue. I'd bet that has something to do with it... But I'm no physicist.

Edit: reference-http://www.virginiasemi.com/pdf/optical properties of silicon71502.pdf
 
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Justin Marx said:
Nooooo, don't over expose.. Do your best to expose properly for your scene.. If you have a black BG, just make sure you don't "under expose" your scene, as noise will be harder to deal with..
Click to expand...

Thanks, that makes a LOT more sense to me. haha. Well in that case, do you have any special practices in low light situations where you don't have total control of light? and your histogram is on the low side? For the most part it's out of your hands and it seems like people don't recommend bumping ISO, so just do your best to expose and work with it in post?

sorry for all the questions, just trying to learn as much as I can quickly.
 
J Taylor said:
Thanks, that makes a LOT more sense to me. haha. Well in that case, do you have any special practices in low light situations where you don't have total control of light? and your histogram is on the low side? For the most part it's out of your hands and it seems like people don't recommend bumping ISO, so just do your best to expose and work with it in post?

sorry for all the questions, just trying to learn as much as I can quickly.
Click to expand...
Do you best to keep you ISO at 800, then bring your brightness up in post.. Don't mess with exposure or ISO over 1250 ish..
im not the end all with info here either.. Just learning from my mistakes..
 
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