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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 :)

Scarlet ISO noise

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Bryant Mock

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We are getting noise at 800 and 400 ISO in a studio at 5600k 180deg 23.97. This has never happened until firmware 5.1.14 update. We have check everything. Anyone else having this issue?
 
black shade?
 
Looks pretty underexposed to me. Looks like it needs to be at 3200 ISO for proper exposure. It's impossible to see noise patterns in a still image though.

Screen%20Shot%202013-10-16%20at%204.35.48%20PM.jpg
 
Ouch... when light is at a premium, f8 may not have been the best choice. Was there a reason for f8? BTW, how are you judging the noise? Are you playing back in redcine at full quality?

Bryant Mock said:
FWIW, we were also shooting at f/8
Click to expand...
 
Your white balance was a bit off but even then your footage is underexposed and you're currently lifting a bit of the blacks. Bring down your black levels to 0 IRE and you'll notice the image is underexposed.

Screen-Shot-2013-10-16-at-1.37.17-PM.png


This is bringing the blacks down to 0 IRE:
Screen-Shot-2013-10-16-at-1.43.37-PM.png



Whites brought up to 90IRE and blacks to 0IRE:
Screen-Shot-2013-10-16-at-1.44.02-PM.png



Talent at those levels:

Screen-Shot-2013-10-16-at-1.44.44-PM.png


Bringing up the mids will introduce noise but a little bit of noise reduction will fix it. Just remember to bring your blacks down to proper levels.

Screen-Shot-2013-10-16-at-1.50.05-PM.png




Proper Exposure for this shot was around 3200ISO with a slight pull down on the blacks. This just shows that the shot was underexposed by almost 2 stops. Use some noise reduction and call it a lesson learned. Next time make sure you have a proper exposure and you won't see any noise.
Screen-Shot-2013-10-16-at-1.54.48-PM.png

Screen-Shot-2013-10-16-at-1.55.02-PM.png


Edit: Bob beat me to it.
 
I'm with Bob, it looks like at least 3200 to get the highlights approaching where white needs to be, my guess would be that you've looked at the histogram while shooting and made sure that it's all in the middle, when in reality you're shooting against what you probably want to be an almost white background, which should have that major peak in the histogram ( that represents the white background)much further towards the right of the histogram.
 
Bryant Mock said:
FWIW, we were also shooting at f/8
Click to expand...

You could have gotten a near perfect exposure for the shot at f4. How were you monitoring exposure and did you use a light meter?
 
We are using a light meter, we just tested it again and it said to shoot at f/8. We appreciate your help Matt (and others). We're using the look you had sent us for the duration of our shoot today just to be safe. We even contacted RED support and sent them a log file. Their answer was we were possibly the wrong compression rate. We were at 8:1, they said to set it to 5:1 or lower for f/8. Even at a lower compression rate we're still seeing grain in the blacks, so we're just going to heed your advice on shoot with the settings you had sent us, which we greatly appreciate! We hadn't had a problem with grain in the past on controlled shoots and we just updated the firmware in the past few days so we didn't know if the firmware update had something to do with it.

We'll see how things turn out and report back! Thanks again everyone!
 
Bryant Mock said:
We are using a light meter, we just tested it again and it said to shoot at f/8. We appreciate your help Matt (and others). We're using the look you had sent us for the duration of our shoot today just to be safe. We even contacted RED support and sent them a log file. Their answer was we were possibly the wrong compression rate. We were at 8:1, they said to set it to 5:1 or lower for f/8. Even at a lower compression rate we're still seeing grain in the blacks, so we're just going to heed your advice on shoot with the settings you had sent us, which we greatly appreciate! We hadn't had a problem with grain in the past on controlled shoots and we just updated the firmware in the past few days so we didn't know if the firmware update had something to do with it.

We'll see how things turn out and report back! Thanks again everyone!
Click to expand...

Your meter is most likely picking up the white cyc background. Open up to an f4 and as long as you don't clip your whites (check right goalpost), your exposure will be good and noise free. Give that a try and see if it helps along with a 5:1 compression ratio. You want that white cyc to be real close to clipping without doing that.
 
Combined your settings and the lower compression rate and everything is turning out nicely! Thanks!
 
expose for what is important and is there. In this case, the skin. F8/3200 ISO sounds like a bad combo. @F4 you would have about the right exposure for the skin here.

If you use a lightmeter, check what you are metering for. "everything" is rarely equally important in an image....
 
Should probably just throw that light meter out the window, because it's making you expose worse than without it!
 
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