Noise on dark parts of video

ccf

ccf

Member
Since I've never read about this problem I'm hoping that maybe its just my camera-

The following grab explains my problem...

noise.jpg


On the computer the noise isnt there, but on a TV the noise is very apparent on the blackest part of the video (inside the truck). Why is the noise showing up on dark parts of my footage? If I underexpose the picture the noise gets worse. Ive tried a million different settings but cant get a clear picture :(

Any suggestions?
 
try bumping the contrast up enough that makes that dark area black. When it plays on tv, the noise should be gotten rid of. If that does unwanted things to your vid, try lowering the saturation as well.
 
I have also found a significant benefit of using an 85b filter while shooting daylight balanced scenes. keep your camera set to 32k, or close to it and your good to go.
 
Detail coring doesnt seem to do a thing, and bumping the contrast just makes the overall image look un natural. But thanks for the suggestions!

Thanks scharky, I'll try this out. What exactly does an 85b filter do?
 
Just tried it on a different monitor..and yes the noise is still there. I shot with the master pedestal from -3 to 0 and it didnt make a difference. The image is pretty saturated, but chroma was at 0. The only time the noise less aparent is when I use a color temp of 2 to 7, but the image is really blue. Arg!

It doesnt make sense that those areas are noisy...Im not trying to make them brighter. So nobody else experiences this? My buddy is getting a DVX in a week so I'll compare the two :)
 
John_Hudson said:
I am not seeing any noise on my monitor. Looks perfectly black. The RED however is pixy style.
Click to expand...

Youre viewing the still on a TV (broadcast monitor?)? Sorry I dont know the lingo for this..
 
Hi,

I downloaded your image and opened it in my editing system, played it back in my broadcast monitor and I couldn't see any strong noise in the black area, maybe because it is a still. But I found it very saturated and blacks bellow 0, see the graphics bellow:


vector.jpg


Are you using 0 or 7.5 IRE ?

Check your monitor brightness using a color bar as well.

Ulisses
 
John, is this a still from interlaced footage? What kind of interconnection (analog?) are you using between yr PC and yr flatscreen?
 
CCF
to get back to your question, the 85b filter balances daylight to 3200k, or tungsten balance. Since the cameras native CCD's are closer to tungsten than to 5600k (daylight) there is less gain that needs to be added to the ccd's to correct white balance. It really works well, I have done some pretty extensive testing.
 
scharky said:
CCF
to get back to your question, the 85b filter balances daylight to 3200k, or tungsten balance. Since the cameras native CCD's are closer to tungsten than to 5600k (daylight) there is less gain that needs to be added to the ccd's to correct white balance. It really works well, I have done some pretty extensive testing.
Click to expand...

Can you post some stills for proof ;)
 
Thanks Jeffery, I'll try that tomorrow. Whats impedance? Pedestal?

Scharky...sounds like I'll be trying this too, what kind of 85b filter should I buy? How do I tell if the balance is closer to 32 or 56 k? Thanks everyone for all the help!
 
Ok, CCF
I posted a little test I did a while back. it is about 14MB and the compression used was the least amount possible. IT is visually accurate to the original DV file.

http://www.stefweb.net/noisetest.mov

This image is blown up 400% and the brightness has been raised so that the noise that comes from the image is enhanced. Basically it is pretty ugly, but it is a good example of using an 85b filter. You will notice that in the lighter dark areas, noise is greatly reduced. Again, the gain on the image was boosted in post so it is much grainier than a standard image.
to tell if you are closer to 32k or 56k you can use the presets that tell you, or you can just think about it logically. If you are using no filter, and you white balance under daylight, you will be closer to 56k. if you white balance under tungsten light, you are closer to 32k. If you white balance in daylight, using an 85b filter, you will be closer to 32k.

hope this test helps you out. While it is blown up like this it is hard to appreciate the still noisy picture, but the final image will be much more pleasing to the eye, grainwise, in the elimanation of the grain.
 
Wow! Genious scharky genious. I just tested the 32k prst without the 85b filter and all the grain dissapeared. Chrystal Clear! Thankyou so much, I would have never guessed it had to do with the white balance. I'm off to buy an 85b filter!
 
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