Welcome to our community

Be a part of something great, join today!

Log in
  • 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 noisy at 2K

D

David Pienaar

Active member
Joined
Nov 13, 2010
Messages
34
Reaction score
0
Points
0
Has anyone else experienced this problem? My epic is extremely noisy at 2K. It is beyond unusable. Just a snowstorm.

I have tried lodging an enquiry with red about a weak ago, very little response from the tech department.:furious3:

Has anyone else had/ solved this problem?
 
What settings? ISO? Light conditions? Going to need to be much more specific to get some feedback.
 
Was at 800iso, very flat lighting conditions and exposed right in the middle. 25fps and 300fps, same issues.

There also seems to be some compression issues. The blacks seem to crawl with pixelation. I used RCX to transcode to ProRes 422 with full debayer.

I have uploaded a R3D file for Red to look at, but no real response except for that they are looking at it. Getting a bit desperate and thought I might try asking around.
 
Yes, I also made sure I did a black balance while camera was set to 2K.
 
I also noticed the footage being very noisy at 2k.....but I thought maybe that was due to the 300fps shooting. Even in really bright daylight, at iso 800, the footage is indeed very noisy. Yet it's clean on 5k 96fps....
 
sounds like you just have a problem with your render settings. What frame rate? red code? do you have enough light?
Are you using latest Redcine X?
Have you tried shooting the same scene at 5K?
how are you rendering your footage.? What are your settings?
 
Maz Mawlawi said:
I also noticed the footage being very noisy at 2k.....but I thought maybe that was due to the 300fps shooting. Even in really bright daylight, at iso 800, the footage is indeed very noisy. Yet it's clean on 5k 96fps....
Click to expand...

2k's not noisy, when you shoot 300fps your compression is higher...hence more noise. Always shoot high frame rate footage at the lowest available compression.
 
When you do the black calibration the camera should be warmed up, don't do the black calibration right after camera turn on, then setup and start making takes half an hour later, rather do the setup while the camera warms up, then do the black calibration just before the take is shot.

That's one reason shooting True RAW is better than REDCODE (tm) or Cineform (tm) or H.264, in compressed formats the black level is very important for the compression since the way shadow details are delt with varies from midtones and highlights to some degree, and if the black level goes up as the sensor heats, then sensor noise can be recorded with greater "focus" and get "enlarged" or in other ways look worse. With actual ADC output recorded as is, in post you can adjust the black calibration off set to re-center the black level for the shadow noise filters, and you can also do black calibration BOTH before or after the shot is made, doing the black calibration after the shot is made has the advantage that if any pixels go bad during the shot they will be masked, if you can only black calibrate before recording then the bad pixels will not get masked, unless there is a hardware masking built in. Once the black level is off, the compression encoder will "burn in" artifacts relating to the sensor noise and FPN to the compressed recording in a way that can be just about imposable to reverse.

Epic is a remarkable camera, but I would hope at some point RED would have the option for True RAW ADC output recording that is not sensitive to black level calibration and so not carry any sort of "burned in" artifacts that compression might introduce, if only under abnormal circumstances.

There may be some issues with the adjustment of the noise filters in the camera not compensating for the lines per image height difference so the extra noise in 2K images is not as well "tuned" as for 5K size noise. Some firmware adjustments to the noise filters in the compressor may help improve the 2K results.

At higher EI/ISO settings the ISO adjustment S-curve gets very steep at the lower end, so it acts as a "gain" factor for any drift of the black level. Exposing higher on the sensor limits puts the shadows more into the lower contrast part of the foot of the S-curve so making any drift lower in contrast, so if you are having black level drift issues from high heat or cold air around the camera, shooting at lower EI/ISO numbers may make it easier in post to "crush the blacks" more to make any "float" in the black calibration point less noticeable.

If you see vertical bands of noise or "lines" those are normal CMOS sensor FPN, I don't know if Epic has built in FPN masking, but the original RED ONE does not seem to have had that since such FPN can be seen in some footage. It might be possible to mask such FPN in post, but you need to shoot about 15 seconds of "black" frames that can be averaged to make the mask file, preferably 16bpc. Again such FPN is more of an issue at higher EI/ISO since the ISO curve has steeper parts and so adds gain to those tones making noise higher in contrast.

If nothing else helps, try shooting at EI/ISO 320 and use more fill light than looks right on the camera monitor (in addition to normal rim lighting etc. in the right ratio to avoid over-exposure) then "crush the blacks" in post to get the fill lighting back down to what looks right. You can always push the contrast of the highlights and shadows down, but if you don't have good detail recorded you cannot as easily pull good image data back out of noise or clipping.
 
I never warmed to the look of 2k on the Red One but a lot of that I think had to do with being 1:1 on the sensor and only using the centre of the lens as opposed to having a compression or processing issue.

I love the massive oversampling 4k/5k offers.

Could it be that you are seeing? I found my Red One 2k footage to be a bit "lumpy," which isn't too scientific but there it is! Maybe post a few seconds of your ProRes or maybe a cutdown of the R3D?
 
If you look at the red and blue separation images you will probably see that they are not as sharp as the green image and have more noise, so when you use 2K mode for 2K those aspects carry over to the end use, when you shoot 4K/5K the red and blue get reduced in size so their fuzziness is halved.
 
Howzit David, ol' high school friend...

1. yeah, send us an R3D or just an excerpt thereof :)

2. Red at 2K will be always be noisy if you don't throw enough light at it. Its such a tiny crop of the sensor. More so than the difference of going from 35mm to 16mm film blown up to 35.

5K looks super smooth because you're taking those 5120x2160 ixels and averaging them down to 1920x1080. Like 35mm. Which also averages out the noise. 2K is just using the tiny center bit of the sensor. Also, it is going to look quite a lot softer. Because it's a Bayer array. At the pixel for pixel level it's only sensing red OR green OR blue - and making a good guess at the rest. So when you throw 5120 sensor pixels at it and tell it to figure out a good 1920x1080 RGB image, you're beyond golden. With 2048, sometimes it can't figure out the precise RGB values per each pixel. Plus then there is a slight optical low pass filter to prevent that whole Canon 5D moire look :P which makes things look a tiny bit blurry pixel for pixel. Although you can add a little sharpening to taste. But if you sharpen it more... this brings out the noise.

I'm not sure why you're even thinking of using 2K if it's not for the 300fps thing. If you can get away with 120fps or less just go 5K - and love it :)

Otherwise, shoot 300fps with a ton of light and I think you'll be OK. Also, look into Neat Video - it's a fantastic noise reduction plugin.

When digitizing film, there were sometimes sophisticated noise removal things going on in the telecine. Same with a F900 or 5D - they're removing noise in the chip before recording. Since RED records RAW, you need to remove the noise afterwards. The benefit of that is you can use smarter noise reduction plugins that have higher quality. Also you can choose how much you need after the fact, which is really useful.

BTW, check out DaVinci Resolve's built in realtime noise reduction too!

Anyway, hit me up with a PM or something - and let's grab a slice of pizza at Tarquino Bake next time I'm in Jo'burg :)

Bruce Allen
www.boacinema.com
 
There is more to this than just noise. I'm assured that Red are working on it though, so whatever you're seeing besides plain old noise and 2k softness, don't panic, just be aware. Certainly however I'd avoid 300fps at anything but 7:1 right now.
 
Two weeks ago on an otherwise spectacular Epic shoot, we had some awful noise on one scene, shooting at 5K 2:1, 60 fps, 8:1 compression ratio. It was a static shot with 14mm lens, looking at a background of trees and forest, talent crosses the frame in foreground. Her coral colored blouse was extremely blocky - looked like bad internet compression. I'm not a compression expert, but I'm wondering if it may have been caused by two factors:

1) The background was a forest of leaves, tiny in the frame, a lot of detail. 2) Because we were in a hurry, we set the camera low on a furniture pad, and I used my left hand as a wedge underneath the front of the camera. Rock steady to the eye, but I wonder if whatever tiny movement there was forced the compression algorithms into overdrive on the highly detailed background. When the actress entered from the left as a large block of moving red magenta, the camera couldn't handle the new information.

It seemed to me either related to levels of detail in the frame, as above, or for some reason, the camera shifted into 30:1 compression for the one scene.

Otherwise, I was crazy for the camera, and can't wait to get my own.

Tim Eaton
 
Red are aware of this and probably beavering away right now. I won't go into detail, as its not fair to the tech guys to have a bunch of people worrying about a problem that is mostly benign, but I've found repeatable scenarios that give me significant compression artifacts, right across the gamut of frame rates and sizes, even at 6:1/7:1 compression rates. 300fps issues put me onto it, but I can make it happen even with camera default settings. I've every faith they'll fix it - however this is exactly why it still says the M "is intended for users who can provide testing and constructive feedback directly to RED" right there on the store when you buy one ;)
 
I went to all sorts of elaborate lengths to try and fool the codec, to no avail. On the other hand some very simple tests have proven repeatable! Computers are strange things :)
 
as a side note...i noticed some strange pixelation/noise or compression artifacting when shooting a scene with very high detail....and lots of contrast....for instance a wave pouding the beach and covering the sand quickly with white foam rushing over the red colored sand....This was VERY STRANGE to see after transcoding the footage and had me going back and forth SEVERAL times to see what the problem was....I have yet to bring this up with RED, AND would be surprised they don't know about it already...not a noise issue as much as some kind of compression artifacting---it's like the sensor is confused and does not know what to do with the high detail areas.......??
 
You must log in or register to reply here.
Back
Top