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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 :)

Epic-w - Noise Pattern - Is this right?

Zack McTee

Zack McTee

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All the footage I'm shooting with the epic-w looks awesome, and I haven't had too many complaints - especially with the changes in ipp2 that fixed a lot of the banding.

I did a fresh auto black shade today after updating to the new firmware. When I booted up the camera, I had an 85mm lens closed all the way, and I noticed there were a lot of horizontal lines in the noise of the blacks.

When I push the exposure heavily in redcine-x I can see the effect exaggerated. I guess I'm just curious if this is the normal noise structure of this sensor. I don't think I notice it when everything is exposed correctly, but I'd like to know if that is normal.

Here's a simple screen grab:

https://s28.postimg.org/6jpn0wiql/Screen_Shot_2017_01_10_at_6_51_47_PM.png

and here's a link to an r3d:

https://we.tl/l7eLy0wume

I appreciate any info.
 
Doesn't appear that you're alone, Zack. There's two other post about weird noise artifacts after firmware updates, though ours were horizontal versus vertical. Do yours seem to dance around the screen and flash?

Let's hope there's a solution soon. I was told to send my camera back in. Is that screen capture a crop or an 8k full frame grab?
 
You're on iso 12800. Offcourse you will see noise then, it's not an a7s.

Looks perfectly fine otherwise.
 
Hi Zack,

If you're seeing it on your monitor, as Luca said, check if Focus Assist is on. In my experience it's a result of the sharpening that's used, combined with low light that makes it appear "noisy". When I turned it off, I couldn't see any noise on the monitor, even at 6400 ISO.

Also, turning the ISO up to 12800 will definitely show noise. But I took a quick look at the R3D, and I could still see some banding at 6400.

Before you recorded the clip, did you let the camera warm up first? You mentioned you saw these artifacts upon boot-up. Also, excuse me for the stupid question because I'm sure you did it properly, but when you blackshaded, you did it after it reached operating temperature?
 
I've had vertical line issues too - have calibrated to project settings as well as auto calibration and nothing seems to work perfectly.

Auto calibration - in a black room, brought up to temp. - seems to be much better at resolving the vertical line/patterned noise when confirming calibration w/ FLUT pumped to +8.
 
Yesterday I read someone bashing on Blackmagic's camera because they have a Fixed Pattern Noise issue that can't be resolved whatsoever.. Is this the same kind of thing?
 
I noticed this issue since receiving my EW in November. I almost contacted RED about it but I thought it was just normal. Every time I do a firmware update I get those weird lines too. I also have to manually calibrate the sensor 2-3 times before getting a usable calibration, as the first calibration seems to give poor results. The best way to check your calibration is to go to the "FLUT" control on your camera, and while the lens cap is on, raise the FLUT control to the max setting. This will let you see any pattern noise or lines that shouldn't be there. IMO, the picture above of your calibration looks ok compared to what I have on my camera.
 
I've had a similar issue with Auto calibration, where within the first 5min of operation the sensor temp and auto blackshade setting were such that the noise was much stronger than usual, but then as I was investigating it, the camera came up to temperature and the camera automatically switched into a different calibration setting and the noise suddenly disappeared. The big problem with this is that the camera doesn't change calibrations while rolling so if I were to have rolled in the first 5 min of the camera being on I could've had a screwed up noise pattern that might have even gotten worse due to further calibration mismatch as the camera gets hotter on all my footage no matter how long I rolled.

One consideration is that it may be nearly impossible to build a calibration that accounts for the sensor temperature that exists during the few minutes it takes for the camera to get up to temperature since the calibration process takes so long. Perhaps auto calibration can't really account for different sensor temperatures because it does not have access to them.

Moral of the story is maybe don't ever roll until the camera has been on for a few minutes or you may ruin your footage. I hope there is a way around this. This is a strong argument against swapping batteries right before roll...

I wonder how other manufacturers handle this.
 
Blackshading doesn't require the same level of attention on other high end cameras: Alexa, Amira, F55, Varicam. It's frustrating that we're still dealing with it to this extent when other manufacturers seem to have handled it years ago.
 
How often are you 8 stops underexposed on other cameras? Let your camera warm up guys, you'll get fpn on other sensors as well if the temperature changing dramatically and you're really underexposed. My camera doesn't cool down fast enough in the time it takes for me to quickly swap a battery either, so I don't see this as being a problem. If you need to be ready to record at any given second, keep the camera on (mine stays on the whole shoot except for battery changes and lunch) or pick a camera system that boots up faster.
 
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