Excessive Noise on Epic Green Screen shoot

[benedictspence]

Hi all,

I have a friend who did an Epic shoot with my camera, they've come back with a lot of noise in the image.... It was shoot on green screen under tungsten light at 800iso. Now I've shot on the Red One green screen with tungsten; I can't remember how I rated the camera but the image was fine. Apparently the noise is so bad it is un-keyable. Has anyone had this problem before? I thought tungsten was okay on the epic, even at 800iso. The camera had been out on jobs before and since without problem; could the camera have forgotten it's black shading momentarily? Another wierdness was that the R, G, B gains had all come up to 1.8 on the metadata.

I know my friend knows how to expose for Red and I had a glance at the image and it looks correctly exposed for 800iso but just noisy. Normally I'd say not the end of the world but I'm being told that it is so bad it is not keyable at all, noise reduction programmes might work however.

Finally, I was told that the image on the monitors was totally noise free. I understand 100% how the Red works regarding RAW and monitor outputs. However if it's possible for the camera to output 1080 with no noise why does it now show up in post.

Does anyone have any thoughts? I honestly don't know what could be causing the footage to be so noisy it's unusable!

Ben

 

[Carey Lee Coffey]

Have you eliminated your computer as a possible cause?

 

[Joseph Hutson]

I find that it's very important to Black Shade regularly...

 

[Kobe Van Steenberghe]

Maybe you can provide us with an R3D still or even better a small clip (1 sec) so we can see the noise moving, then we can have a look at what is going on.

You should also contact red support if you think something is wrong.

 

[Jeff Kilgroe]

BLACK SHADE!

And it may just be under-exposed. I've seen plenty of bad green screen, especially when the screen is under-lit and/or not appropriately lit to balance with the subjects in front of it.

This is all academic unless we can see some samples.

 

[Brad Allen]

Just wondering if someone could send me a link where to I can find some more detailed information on black shading (as well as Light and Light24 shading)? Just trying to get my head around what is actually being calibrated and what the process involves. Took a look through the EPIC manual but there was only information on how to do it, rather than info on what it actually is and why it is done.

 

[Björn Benckert]

Have you eliminated your computer as a possible cause?

Normally the fault is right behind the computer or camera...

 

[Zeb B]

Just wondering if someone could send me a link where to I can find some more detailed information on black shading (as well as Light and Light24 shading)? Just trying to get my head around what is actually being calibrated and what the process involves. Took a look through the EPIC manual but there was only information on how to do it, rather than info on what it actually is and why it is done.

+1 on that

 

[Justin McAleece]

If all the RGB values were way up then it could mean they were vastly underexposing and not knowing it.

 

[Justin Kirchhoff]

I'll sound like a broken record here, but you need to BLACK SHADE before every shoot. It's the most important thing anyone can do before they start rolling on takes.

I was shooting outside just last week, didn't black shade because of conditions out of my control, and when I was grading the footage I wasn't too happy with the blacks in the image. They were noisy as hell and I was shooting outside in the bright Texas sun...it wasn't right.

So now I black shade before I shoot. No matter the conditions. It's worth the 10 minutes it takes. Every second.

 

[Erich Ocean]

I'll sound like a broken record here, but you need to BLACK SHADE before every shoot. It's the most important thing anyone can do before they start rolling on takes.

I was shooting outside just last week, didn't black shade because of conditions out of my control, and when I was grading the footage I wasn't too happy with the blacks in the image. They were noisy as hell and I was shooting outside in the bright Texas sun...it wasn't right.

So now I black shade before I shoot. No matter the conditions. It's worth the 10 minutes it takes. Every second.

Am I to understand correctly, then, that having your Epic by your side and whipping it out to grab a shot or two at sunset is a pipe dream? Because sitting around for 10 minutes doing a black shade while the light is changing sounds...not cool. Can anyone chime in here?

 

[Zeb B]

I'll sound like a broken record here, but you need to BLACK SHADE before every shoot. It's the most important thing anyone can do before they start rolling on takes.

I was shooting outside just last week, didn't black shade because of conditions out of my control, and when I was grading the footage I wasn't too happy with the blacks in the image. They were noisy as hell and I was shooting outside in the bright Texas sun...it wasn't right.

So now I black shade before I shoot. No matter the conditions. It's worth the 10 minutes it takes. Every second.

Define "every shot". You mean like once a day, at each power up or before every shot you take? What is the prescribed frequency and why? RED TEAM can jump in here at any time.

 

[Carey Lee Coffey]

Define "every shot". You mean like once a day, at each power up or before every shot you take? What is the prescribed frequency and why? RED TEAM can jump in here at any time.

I'd love to know the answer to this too. Do you black shade before every set up, or at the beginning of each day? What about going from interior to exterior? Or day to night?

 

[benedictspence]

Hi All,

Thank you all for your help on this one. There seem to be mixed thoughts on this one. Either operator error or camera error. This is exactly what my problem is ; I don't know which as both seem unlikely. It's defo not the comuter as it's been tried on different machines and output to a monitor and it's there.

I don't think it's operator error as the DoP is competant and know how to expose for Red. Tungsten @ 800iso on green screen might be a culprit though...

So if it's black shading how often should we be doing it? Every morning? After lunch? Could Red build in a timer? Is it a temperature thing or does the camera just forget after a little while? If so how long? Every speed or shutter angle change? (that would suck!) I'm pretty confused and there is nothing from Red about when and how to often to black shade. I thought it was after every firmware upgrade, then the camera would save it.

The director is currently in communication with Red about this; I'll try and get hold of some R3D's and upload them.

I've a funny feeling it's a bit of both compounding each other...

Ben

 

[Jon Thomasberg]

Jeff is correct... do a black shading when your temperature changes environments from when it was last black shaded... it helps, you might not be able to always see the difference, but it's there.

body caps is always good or lens completely stopped down just to make sure... and I usually throw a towel or shirt or something over the front of the camera just for extra measure as the calibration process is extremely sensitive to light.

Also, as Jeff Kilgroe and others have pointed out. It is best to perform the black calibration after the camera has had a chance to 'warm-up' (read: powered-on and had sufficient time to get up to a normal operating temperature and sustained for a few minutes BEFORE performing calibration)

Hope this helps

 

[Jake Bastian]

A good rule of thumb is to black shade after every change of frame rate.

I think it's most likely a combination of black shading and tungsten lighting though. Some people on here don't agree with me, but I feel very strongly that if you're going to be shooting chroma sensitive material, best practice is to work as close as possible to the camera's native sensitivity. That means daylight bulbs pointing at your green screen - at the very least tungsten bulb with some kind of daylight filter - even better would be chroma bulbs pointed at the green screen so you aren't contaminating the screen towards either red or blue but if it's cost that's keeping you using tungsten then it'll definitely keep you away from chroma bulbs as well. Plus spill control with chroma bulbs can eat into your day.

 

[Mark Deeble]

It would be really good to have RED come in on this - it's a question that has been raised several times before and user suggestions seem to be to black balance:

1. After a change of frame rate
2. After a firmware update
3. After a big temperature change

I regularly change fps several times an hour when shooting wildlife EFP and it is simply not feasible to black balance every time, so I don't - especially as there is no knowing which speeds I am going to need.
When shooting cineform RAW with a Si2K I would black balance once when the camera was switched on and then when the temperature had stabilised and after any big temperature change (10 deg C) thereafter. The black balance on that camera takes a few seconds so there is little down time if the operation needs to be done several times a day. Black balance on the Epic seems a more complex operation and takes much longer and can result in significant downtime, especially if it needs to be done in the middle of a day's shooting.
What is the advice?

 

[Jon Thomasberg]

I don't work for Red, but to save them the time, Jim and Deanan have already weighed-in on this ~18 months ago. Outcome was:
-upon firmware updates;
-upon extreme temperature changes;
-especially important for long exposures (not merely framerate changes) [Jim's add]

Also, black calibration is an additive process from the previous calibrations, in that if a pixel was stuck last time and has become unstuck this time, it will still be considered stuck. Conversely, a calibration reset will zero all previous calibration results and start fresh. If you do reset, make sure to perform a new calibration afterwards to give the camera at least 1 baseline test by which to operate.

Also, changing kelvin temps (e.g. tungsten to daylight) does not change anything with black calibration.

 

[Zeb B]

Thanks guys - would love the TEAM RED Myth Busters to address this when able with a best practices list to make sure we're all good

 

[Mark Deeble]

Something that has caught me out a couple of times is that even if the project its set at 25fps and the current fps is set at 25 and 1/50th, if you select Black Shading and then select the second option - at the current FPS/Exposure, then while performing the black balance the lcd seems to display the 24FPS and exposure at 1/48.
This caused me to abort the process a couple of times until I realised that it seems to happen every time - is this common experience?

The process currently takes 12 minutes ... whether that is fine or not depends on how often I should be doing it...?