Yes, another noise thread

KyleProhaska

KyleProhaska

Veteran
I was on the fence on whether or not to sell this camera, and decided to keep it. However, I do want to see if I'm doing something wrong here, because after having it for more than a month and a half I'm having some pretty bad noise issues in many situations, even when I'm outside.

My typical settings have the detail turned down and the coring down as well (-3 to -4) as Barry's book states "the lower the detail setting the less effect the coring has on the image." I also choose the cleaner gammas like B.Press and Cine-V and the cleanest color matrix which is Norm2. Even so in broad daylight with my ND on 2 or 3 with my lens stopped down (in varying degrees) to get my exposure I'm finding a good amount of noise. My chroma is turned down most of the time in my settings to so I'm sure it isn't chroma noise.

To me it seems like any mid-tones are getting the worst of it, which unfortunately make up the majority of my images (I think this is typical). I've taken some really clean shots with this camera so it's confusing to me when the noise shows up. I can't figure out what to watch out for to avoid it because it seems to be an on/off thing.

Any comments? I'll admit I forget to black balance often, and I've heard that it makes a HUGE difference, but I've also heard the opposite. Could that be the culprit for some of this stuff? Should I black balance not just when I change ISOs or ND but also when I change my exposure via my lens? Perhaps that's another reason? If I go outside with the camera it's likely I have my ND on 1 then twist it to 2-3 or even 4 then change F stop accordingly until I find an exposure I like. Is it possible that not black balancing when starting at ND1 and going to 2-4 is adding a significant amount of noise?

Here's a quick example (3 seconds, Prores)
http://www.kyleprohaska.com/af100/af100noise1.mov
http://www.kyleprohaska.com/af100/af100noise2.mov

To me there's just no reason for a shot like that in broad daylight to be that noisy but maybe I was just a stop or two underexposed there?
 
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What ISO are you shooting at? Also, are you recording in the native codec?

At first glance (on my cheap $150 23" uncalibrated display), it honestly looked pretty clean to me. On closer look (really pixel peeping) I noticed some slight noise in the darker areas of the bokeh and in the fence in the back as the detail comes into focus, but frankly it looked like fine compression artifacts more than noise to me (when the AF100 codec starts to break, it does so very gradually and organically unlike other codecs), especially as there is fine detail constantly changing focus in the scene such as grass, moving leaves, and the textures of the bark of the tree and the planks in the fence.)
Screen shot 2011-05-26 at 2.53.13 AM.jpg
I have a feeling if that is recorded with an external recorder, that slight bit of 'noise' would be non-existant.
 
The ISO is always 200, I don't think with this camera I've had to increase it at all even in a lot of indoor situations. Perhaps you're right about the external recorder, but in tests I've seen the difference is negligible. I guess my point is the darker areas of that fence isn't too far into the shadow range, and I'm shooting out in daylight where even if it's slightly in shadow, there's plenty of light to help with noise...indoors I could understand.

ADDED Second link to the original post...
 
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Kyle.

I have downloaded the files and I will take a look at them in the edit suite tomorrow.

But for now.... looking at the small frame grab in Oliver Rushes post...the black is over exposed (or lifted). Check his sig avatar to see what Black looks like.

What ever... it is not black and would not sit at black on a WFM. It has no detail in it so I can already tell that it is supposed to be black. That means all other tones are overexposed or in opther words. They do not acurately represent the tones as the sat in the scene.

Can you tell me what lens you shot this with? ( ie does it have an aperture ring and how did you set the exposure?)

Bad exposure (or CC) ...this is what generates the noise.


I will be posting up some screen grabs that show what the camera does at 200 ISO tomorrow. (from our 48 Hr Festival shoot) This camera is not noisy.
 
We never black balanced the first time we got the camera and fired it up to do a series of tests.

Never saw a black that looked like that. (The screen grabs are published in this forum.)

We always do so now FWIW.
 
Yea it's weird because I use B.Press which crushes the blacks the most...and that shot is untouched (no CC) so it's exactly as the camera captured it. No black balance, ISO 200 with ND on and probably a few stops down on my Nikon 200mm (which starts at F4 so maybe 5.6 is where I was at) to get a balanced exposure of the leaves and BG without blowing out anything on the white flowers.

You don't need to show clips without noise, as you saw in my other threads I've gotten clean images from this thing too, hence my confusion. I don't know if the exposure is strictly to blame, or the subject with the wood grain and the kind of shadow it's in is to blame, or whatever. It's tough to know what's wrong there.

Don't forget that the BG was in the shade, so if I was exposing for the leaves that were in direct sunlight, it makes sense that the fence and BG wouldn't be totally black.
 
It's compression and artifacting, nothing more. Try this... Stop watching your clips sitting a foot away from your screen. Hit play and back off your monitor a good 6 feet. Remember when mom said. "don't sit to close to the TV or your eyesight will go bad". She didn't want you to see the noise and compression on the monitor. Who here sits a foot away from their TV? Back up off the monitor!
 
same issues as well, although not in daylight like the clips above, moreso indoors and at night time it doesn't look good without a good amount of light....be interesting to see what others are doing in general to avoid this. i'm hoping it's a user error.
 
Yea I'll just need to try black balancing next time I shoot something to see if that makes a good difference. I was just wondering if there was something happening I didn't see or couldn't guess. I guess not, ah well.

Thanks for the comments...
 
I am not sure if this is the issue in your case, but black balance makes a major difference.
I suspect black balance will help you out.
 
Af100noise1 there was nothing. I didn't see any noise. Looked clean to me. On your second file it almost seemed like the saturation was to high. That may not be the case and a Black Balance should clean it up. The AF100 has noise at any ISO, but the type of noise is very different to my old camcorders. I'm comfortable shooting at ISO1250 for my clients if I have to. Let us know how it goes after you Black Balance and re-shoot.
 
TimurCivan said:
@ ISO200 there should be absolutly no noise.

somethign is wrong somewhere....
Click to expand...

Maybe there's some confusion between noise from the sensor (aka camera noise) and compression artifacts, which can show up at any ISO.

I've recently had ISO 200 material bounce on a tech check on delivery, mainly because of compression noise in the near black areas of an image. You can't really see them unless you blow up the image and go looking. From a creative point of view and for 99.9% watching the content they'd never notice it. But it is there and the boffins take great delight in pointing it out to me. Of course, it's being intercut with RED MX material, so it's more obvious when it's present. I can bet if I shot the whole thing using AF100's they wouldn't say boo.

jb
 
Hey John

Wonder what they would have said if you cut some film into your program?

Recently I cut some AF100 footage in with some 35mm originated footage and I had to "degrade" the Af100 footage ( add noise, faux grain) to get a fit and feel likeness.

Its not til you have footageside by side that you get a comparison
 
After many shoots, in very different conditions, I realized that if I use the ISO at 400, it seems to lessen the noise a little bit.
It does make sense though, since the sensor is "native" 400. In theory you do lose a little dynamic range in the highlights as well at 200.
So now I never go down under 400. Just turn that ND wheel...
 
Does anyone know any good way to shoot low light conditions. I was on a shoot this weekend and I thought I started to see some strange noise on the monitor. I was trying not to go over ISO 800 and light it well.
Anyway know any good tips? I'll see if I can post some pics from the shoot. I just hope it was a monitor issue.
 
GrandLunar said:
Does anyone know any good way to shoot low light conditions. I was on a shoot this weekend and I thought I started to see some strange noise on the monitor. I was trying not to go over ISO 800 and light it well.
Anyway know any good tips? I'll see if I can post some pics from the shoot. I just hope it was a monitor issue.
Click to expand...


Above all, make sure to get a proper exposure. That is the key to clean footage at any ISO. I have shot by candle light with my AF100 (fast glass helps) (http://vimeo.com/23777030)
 
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