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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 :)

Avoiding Noise in the Shadows

I don't think it's reasonable to expect the blue channel to be completely noiseless in 3200K -- just as the blue layer in 500T film stock is the grainiest layer.

The question is simply does the final overall image look too noisy to you, or is it only noisy when you do things like just look at the blue channel alone.

But probably if you want less noise, you shouldn't be rating the camera at 500 ASA, though I don't think the noise at 500 ASA is that objectionable with Build 16 myself even in 3200K. But it's not noiseless.
 
IMO, you make the final call viewing all channels at 24fps ( or 23.976, 29.97) ... i take 4k down to 2k then edit ... if i stop on a 2k still frame i do see more noise then at 24fps ... also i see less noise projected 8ft wide then on 24" lcd ( got me ?) ...
 
Not really a question about noise OR lo-light I guess so forgive me if i'm doing the wrong thing here. New to Reduser BUT increasingly being asked to shoot on the Red.
So here goes, has anyone got anything to say about shooting Day For Night on the Red. Have a commercial next week where they want to keep some detail in the sky at night in a football stadium under floodlights. I figure maybe DFN is the way to go..............

I see Fredi Callinggard in the house, with an impressively low Red no. Pick your brains?

Thanks,

Luke Palmer
 
It's all about what happens before the data gets recorded. When the shot is lit well, the correct aperture is set on the lens, the focus is right on, and the shutter is set properly the images can be quite noiseless and we get the exquisite 4K images we all seek.

But stray away from that process and things get interesting. It becomes very subjective. How much noise is too much? Is the noise characteristic accepted as "film grain-like". Is it just too deep in the muck?

Existing light shots are a challenge if you don't have enough stop with your lenses. As was mentioned, things can get ugly if you are having to push the image too much. I have found that quite often going beyond 500ASA is just too objectionable for me. Post can only do so much to save it. For some shots I've been okay with the noise. Others, not so much.

Expose well, post well.
 
SLR v RED

I think big big issue here is that a SLR with the same size sensor put beside a RED camera in exactly the same 'low light' will not have noise in the blacks.
If I am shooting a brightly lit model that has a background that is dropping into black, at the moment I get beautiful crisp foreground and yukky noisy background on the RED and nice solid blacks on the SLR.
 
mrtimelapse said:
If I am shooting a brightly lit model that has a background that is dropping into black, at the moment I get beautiful crisp foreground and yukky noisy background on the RED and nice solid blacks on the SLR.
Click to expand...

Yay, a fellow timelapse shooter!

Noise in the shadows is dominated by read noise. One component of read noise is the readout speed. At 3-10 FPS, APS-C DSLR cameras do not require the very fast readout speed of the RED ONE. Furthermore, noise is hard to compress. Therefore, if it was demonstrated that an APS-C DSLR truly has less read noise when using analog-gain ISO 1600, I would not be shocked. But I haven't yet seen anyone attempt a real comparison. (I'd do one myself if I had a RED ONE.)

There are many, many ways to perform an incorrect comparison between two similar DSLR cameras, and even more potential pitfalls when comparing with the RED ONE. Shoot RAW? Use IRIS/DCRAW (among the only converters with no noise reduction)? Use the same absolute exposure in both cameras? Used consistent artificial light (not outdoor or anything with even minute variations)? Resized both outputs to the same resolution before comparison? Used the same lens and focal point (noise in out of focus areas is more obvious to the brain)? Measured the difference in dynamic range? Resolution for a given noise level? Propensity for aliasing at that resolution? Post the RAW files from both cameras with the results?

Web sites don't get these important principles of comparison correct. Most of them compare 100% crops of default-settings raw conversions. Many people aren't aware that *every* popular RAW conversion program applies noise reduction. And the far majority of them use different noise reduction for different types of cameras. For example, D3 raw conversions desaturate in high ISO, whereas 1dsm3 is left in full color, leaving the uniformed to draw the wrong conclusion about which camera has better low light performance.

All that only covers a comparison of what the sensor is capable of. Most pepole are concerned about issues that include many other layers, such as how a given camera compares when used with certain in-camera processing (e.g. JPEG). Or when used with a certain post-processing workflow (e.g. REDCINE). But most people a more concerned with other combinations of issues.

By the way, I'm not trying to say that your comparison or findings are wrong or invalid. Only that no one has really answered the question definitively to my mind.
 
You are right that no-one has answered this question. "How do you shoot low-light on a red without getting noise"

The discussions I see regarding channels and high end cinematic techniques are sort of beside the point to me.

I know both the D3 and the RED very well.
It is very difficult to get a noisy image on the D3.
On the Red - it is very difficult NOT to get a noisy image in low light.

So to me at least - It is a very easy comparison to make accurately.
 
mrtimelapse said:
It is very difficult to get a noisy image on the D3.
On the Red - it is very difficult NOT to get a noisy image in low light.
Click to expand...

First you said "SLR with the same size sensor", but now you're saying the D3. The D3 does not have the same size sensor as the RED. It has over twice the area. The laws of physics dictate that the RED ONE theoretical minimum amount of photon shot noise is more than double that of an 36x24 sensor.

As much as I give RED credit, I think breaking the laws of physics is slightly beyond their reach. ;-)
 
Ok, it took me quite a while but I here deliver the images for you to judge and suggest. First of all I will show you a test I did in which this worst case scenario delivers a little or respectable noise over a flat blue background. It was lit with HMI from left to right delivering a gradation between the background. For me, the noise in the right part of the image is annoying, because it distracts. I know its a flat background and all but I have seen others shoot darker, or grayer backgrounds with less noise. So here is the RGB image:
8591_1219793602.jpg


And here is the Red channel which I think shows where the annoying noise is, the blue channel looks good as I suppose HMI lighting renders better:
8591_1219793708.png

On the other hand, I had to shoot a greenscreen spot in which a guy jumped into a skate board. It was lit with tungsten although balance on camera set to 4000K instead of 3200K. The RGB looks like this:
8591_1219793809.jpg

And here is the blue channel now:
8591_1219793849.png

I think its very noisy. Specially in the guy's pants because they are gray almost black. Other channels look decent, but still the answer remains untold. How do you obtain less noise from these sort of images? I see a lot of noise in the blue channel of the second shot but I understand its hard if not impossible not to get that kind of noise there, BUT on the guy's pants I think its too much. Moreover the camera even started copying green from the surroundings which was not good for the chroma key. I dont know what am doing wrong, but I have seen beautiful shots made with the camera that look noise free in same sort of situations.
Any thoughts welcome.
Thanks for the patience.
 
I`ve written some of my personal experiences with build 16 in another threat (red for the big screen), what you`re talking about is the main problem I saw with the cam while testing it extensivley for a 4K-DI printed on premiere for the big screen. So my way to avoid as much as possible that kind of noise in the darker parts of the frame, and also avoiding the clipping in the highlights, is to expose in a range of 4 stops - that`s all. It sounds very unbelievable, but my tests and every day shooting experiences for this actual feature show me the limits of MY cam... probably some other cam may produce better results, whereas I haven`t seen any real good footage without that kind of noise yet, although the CCs are mostly made very well. But this is not the way I`m looking for: to fix it in post. So I have to light for an extremly flat image and I`m pretty sure this is the only way to work with the cam to get the best results out of it. On top of that, I only use HMI-lighting and avoid any tungsten sources.
 
Hello there.
I shot another series of chromas yesterday. This ones with Build 16. Although I still feel the noise in the blue channel is still high I was gladly surprised by the improvement. I set the camera on 3200K and shot everything with tungsten. I just had no budget to do it otherwise. The chromas were excellent, one click keylight did most of the job very smoothly. We tested during the shoot, which was not very intelligent time wise but helped a lot to calm down the 3D and Post guys. I didi exactly what you have just mentioned. I shot as flat as I could. I used 3 set of silks, 2x2, 4x4, and 6x6 meters. I had about 5 stops the most of dynamic range. At first I was worried but when I opened the files in red alert and added contrast to my surprise the result was excellent. Not the way I would have done it in 35mm but at least I knew now how to use the tool. I wonder how everyone else produces those noise free images with high contrast situations. Beats me.
 
Good question. I don`t see a chance to shoot high contrast images without getting noise - for the moment - in the future, for sure. I really had to attune to this kind of lighting and to control more than ever the parameters, but it works and the results are good. I did a small test version of the whole workflow last week: 2K-FCP editing, speedgrade xr CC in 4K, lasered on arrilaser in 4K to masterneg and printed on kodaks premiere...this is the way I will do the whole picture. The results are good. I got my deep blacks with detail in and still can see detail in the whites. No digital artifacts.
 
Rather than starting a new thread I wanted to ask about "rolling off the curve in the blacks" to minimize noise.

From my experience, opening a low-light RAW file in RA/RC always has some noise (B16, ISO320) but I would imagine an unprocessed film stock would as well...but almost any recent film I've seen on Blu-ray (nowadays) has slightly crushed/glossy blacks. Just wondering how much is too much?

My question is, are most of you rolling off/crushing the blacks in RA/RC to minimize noise in the shadows as they will most defintely be in the RAW file?

I'm asking because I recently had a short turnaround low-light project (client needed the files converted by the next morning!) and all I applied was a RedSpace/REC709 look without any curves. Basically I wanted to keep the image as flat as possible but should have gotten "closer" in retrospect. Even at Prores HQ the footage was abit noisy in the shadows and looking back I should have crushed the blacks abit to minimize this.

Just looking for anyone's suggestions and experiences on "rolling off the curve" at the bottom. Basically how much are you guys doing in the first light?!
 
Oliver, your test sounds awesome. I hope we could do that kind of tests here in south america that easily. I know chile and argentina have an arrilaser but still!!! I did another series of tests today. I came to realize the only way you could get a "almost noise free" or "acceptable" image with available light and shadowed areas. Shoot in 5600K. We shot a table lit with some fluorescent light on top, and a bulb (tungsten). Set the white balance to AUTO and it went to 4098K heh! We shot it and it looked like crap. Noise was awful. Then we shot the same scene at 5600K and CC in RA to 3800K It was perfect. I think this is the way to go, and I also think this is how Gunleik and MacGregor did their tests with low light situations. I checked the channels and they were evenly exposed. So I must say I am very happy that finally I got a way around the question I originally asked in this thread which is How to avoid noise in the shadow areas. I will try and post some picts by next week of this test, you know I take some time to do that but please bare with me.

Brian, the trick is to get a little more exposure on the shadow areas. Even if it means to over expose the whole image. Why? Because in RA you can slide the exposure slide a bit down without risking your detail or noise. PLUS in the curve tool you can just roll it lower so that the noise is gone in the blacks and it looks decent. Besides B16 and ISO 320 you MUST consider shooting as near as 5600K as possible. Because of the bayer mask the sensor is much more reliable in this WB than in tungsten setting. I think I will never shoot in 3200K no more. I just cant understand why. I will test if setting the cam in 5600K and filtering it with an 80 filter in front of the lens could do the trick.
Thanks to all. peace.
 
Estebanred. I had the same experience with the auto white function. It never corresponded with the actual color temperatur. So I started setting my color balance only by using the manual function and never lower than 5000K - whatever CT I have to deal with.

Brian. Film emulsions have a much wider latitude than digital. So the "noise" = grain (not talking about individual emulsion grain characteristics) in an emulsion starts to appear a lot later at the lower part of the curve (of a well exposed neg) than in RAW, which means, until you reach that point of "noise", you can already look back to a much wider exposer range and a much more contrasty lit image.

Best.
 
Little update on this issue.
For my workflow, I will end up in SD in 80% of the cases. So I tried and loaded the proxies in FCP transcoded with the log and transfer function with absolutely no correction whatsoever. I shot a worst case scenario shot, a glass with black background in 2K at 113fps, lots of weird noise in the black areas. But guess what, when I uploaded to FCP and previewed it in the SD CRT monitor it looked so good I cant even write about it. It was really refreshing. I wonder the thing with noise depends in: What gamma, LUT you apply to the RAW. The quality in which you monitor and where you monitor your footage. I sincerely think the computer monitor is not the best tool to monitor footage, but while 4K monitors become affordable my guess is to down convert/transcode and judge from there.
For me, tranquility came from the monitor, there was no noise there. Am very satisfied with my test results, and I dont even have my own camera yet, have been testing with friends. So, I will get my own tests as soon as the camera arrives. Hopefully sometime nextweek.
 
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