Images with noise!!! at DVinfo.net

Gustavo da Luz · April 25th, 2008, 03:38 PM

Hello everyone..need help!!
My shots has to much noise when shooting on exteriors..I´m using ND filters, schutter speed for example 1/500..The image is not sharpeness as whell...How can i get sharpeness and no noise images? The interiors are much better than exteriors..why?

Sean Donnelly · April 25th, 2008, 03:56 PM

Do you have detail turned on too high?

Gustavo da Luz · April 25th, 2008, 04:28 PM

Quote:

Originally Posted by Sean Donnelly

Do you have detail turned on too high?

Hi Sean...
Detail is on but all the rest (Level, Frequency, etc) are set to 0.
Skin Tone Detail is also turned on but the rest are standard from factory...

Akira Hakuta · April 25th, 2008, 05:11 PM

Is your iris on auto? Keep it below 8 for optimal image sharpness, and if you're outside, you should be able to set your gain to -3db. Probably most important, shoot at an hour when shadows aren't that harsh and contrasts are very high.

Gustavo da Luz · April 25th, 2008, 05:26 PM

Quote:

Originally Posted by Akira Hakuta

Is your iris on auto? Keep it below 8 for optimal image sharpness, and if you're outside, you should be able to set your gain to -3db. Probably most important, shoot at an hour when shadows aren't that harsh and contrasts are very high.

Hello Akira...
I use manual iris, always full manual...
I will do that tomorrow...
Thanks ;)

Jon Fairhurst · April 25th, 2008, 07:31 PM

Have you looked at the video on a waveform monitor or histogram? I wonder if your images are underexposed?

Gustavo da Luz · April 26th, 2008, 03:13 AM

Quote:

Originally Posted by Jon Fairhurst

Have you looked at the video on a waveform monitor or histogram? I wonder if your images are underexposed?

Hello Jon...

Yes, they are underexposed...but, when i whant to get everything in focus i need to close the iris, well, not close but f11, like in photografy...i wonder if these camera can work like my 35mm nikon...

Gustavo da Luz · April 26th, 2008, 03:27 AM

Quote:

Originally Posted by Akira Hakuta

Is your iris on auto? Keep it below 8 for optimal image sharpness, and if you're outside, you should be able to set your gain to -3db. Probably most important, shoot at an hour when shadows aren't that harsh and contrasts are very high.

As i explained to Jon, close to f11 or f16 to get everything in focus, but I did what you told me to do..below 8, -3db and it works fine, no noise and sharpenes images...

thanks Akira... ;)

Steven Thomas · April 26th, 2008, 08:14 AM

Yes, stay away from f16. You will suffer diffraction which will soften your image. Your images will also show more noise due to less illumination on the image sensor.

I make it a rule to never close more than f8.

Eric Pascarelli · April 26th, 2008, 12:43 PM

also, to add to what Steven said, softer images (when the softening happens before the sensor as with diffraction) show noise more than sharper images.

Dennis Joseph · May 26th, 2008, 04:33 PM

I was shooting last night 1080p HQ 24 with 0 and -3 db gain and I noticed some noise on the videos. I had the iris fully open , manual everything. Is there any other possible setting that I may have missed?

The image was well lit for what I put it through but I still saw noise when there should not have been.

Dominik Seibold · May 26th, 2008, 06:11 PM

Try detail-off. Btw, the crispening-parameter of the detail-settings controls the amount of noise-reduction, but I always feel most satisfied with detail-off (no noise introduced by unneeded sharpening and so no noise-reduction needed. The result is a very clear and natural picture).
Also use cine-gammas instead of std-gammas. std-gammas leave a lot of headroom for aggressive knee-settings, so they are more noisy because of their (digital) extra-gain. I recommend cine1 as a general-purpose-gamma.
Also be aware of the fact, that -3db reduces the dynamic range. So just use it if the scene is not contrasty (when maximum exposure without clipping leads to an overexposed picture). It's a bad idea to use -3db and then underexpose to avoid clipping.
Btw, there are two kinds of noise: Noise introduced by the analog gain-circuits and noise introduced by the a/d-converters. The analog gain-noise looks more pleasing (gaussian noise vs. quantization noise). So always prefer analog gain to digital gain (furthermore digital gain of course always amplifies analog noise. In fact analog gain increases the s/n-ratio because digital noise gets relatively lower).

Seun Osewa · May 26th, 2008, 06:20 PM

Oh for Christ sake he is using multiple ND filters and shooting at 1/500 shutter. Why won't his images be grainy when his ccd isn't getting enough light? Geez.

Someone asks "why is my dead baby not breathing" and you say "check the temperature"?

Jeremiah Patton · May 26th, 2008, 07:55 PM

If you are using the slow shutter try 16 or 32 instead of 64 frame accumulation because at 64 I seem to get a good deal more grain/noise. Food for thought if you were using it.

Leonard Levy · May 26th, 2008, 09:51 PM

Quote:

Originally Posted by Dominik Seibold

std-gammas leave a lot of headroom for aggressive knee-settings, so they are more noisy because of their (digital) extra-gain. I recommend cine1 as a general-purpose-gamma.

Dominik,
Could you explain this idea in more detail (no pun intended) please. I've never heard this before and don't understand what you are saying. On the contrary, most of the experienced engineers I know actually tend to be suspicious of cine gamma type curves.

I hope you don't take offense at the question, but what is your background? - i.e how long have you been doing video, engineering background etc. I just want a context for what your saying since its unusual to me.

I'm interested though.

Lenny Levy

April 25th, 2008, 03:38 PM	#1
Gustavo da Luz Regular Crew Join Date: Jan 2008 Location: Portugal Posts: 46	Images with noise!!! Hello everyone..need help!! My shots has to much noise when shooting on exteriors..I´m using ND filters, schutter speed for example 1/500..The image is not sharpeness as whell...How can i get sharpeness and no noise images? The interiors are much better than exteriors..why?

April 25th, 2008, 07:31 PM	#6
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	Have you looked at the video on a waveform monitor or histogram? I wonder if your images are underexposed? __________________ Jon Fairhurst

May 26th, 2008, 06:11 PM	#12
Dominik Seibold Major Player Join Date: May 2008 Location: Nuremberg, Germany Posts: 285	Try detail-off. Btw, the crispening-parameter of the detail-settings controls the amount of noise-reduction, but I always feel most satisfied with detail-off (no noise introduced by unneeded sharpening and so no noise-reduction needed. The result is a very clear and natural picture). Also use cine-gammas instead of std-gammas. std-gammas leave a lot of headroom for aggressive knee-settings, so they are more noisy because of their (digital) extra-gain. I recommend cine1 as a general-purpose-gamma. Also be aware of the fact, that -3db reduces the dynamic range. So just use it if the scene is not contrasty (when maximum exposure without clipping leads to an overexposed picture). It's a bad idea to use -3db and then underexpose to avoid clipping. Btw, there are two kinds of noise: Noise introduced by the analog gain-circuits and noise introduced by the a/d-converters. The analog gain-noise looks more pleasing (gaussian noise vs. quantization noise). So always prefer analog gain to digital gain (furthermore digital gain of course always amplifies analog noise. In fact analog gain increases the s/n-ratio because digital noise gets relatively lower). Last edited by Dominik Seibold; May 26th, 2008 at 07:02 PM.

May 26th, 2008, 07:55 PM	#14
Jeremiah Patton Regular Crew Join Date: Apr 2007 Location: Nanaimo BC Canada Posts: 31	Try using a faster frame accumulation If you are using the slow shutter try 16 or 32 instead of 64 frame accumulation because at 64 I seem to get a good deal more grain/noise. Food for thought if you were using it.

April 25th, 2008, 03:56 PM	#2
Sean Donnelly Regular Crew Join Date: Jan 2008 Location: New York, NY Posts: 188	Do you have detail turned on too high?

April 25th, 2008, 05:11 PM	#4
Akira Hakuta Regular Crew Join Date: Feb 2008 Location: Washington, DC Posts: 44	Is your iris on auto? Keep it below 8 for optimal image sharpness, and if you're outside, you should be able to set your gain to -3db. Probably most important, shoot at an hour when shadows aren't that harsh and contrasts are very high.

April 26th, 2008, 08:14 AM	#9
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Yes, stay away from f16. You will suffer diffraction which will soften your image. Your images will also show more noise due to less illumination on the image sensor. I make it a rule to never close more than f8.

April 26th, 2008, 12:43 PM	#10
Eric Pascarelli Major Player Join Date: Nov 2007 Location: Los Angeles, CA Posts: 498	also, to add to what Steven said, softer images (when the softening happens before the sensor as with diffraction) show noise more than sharper images.

May 26th, 2008, 04:33 PM	#11
Dennis Joseph Major Player Join Date: Jan 2008 Location: Chicago, IL Posts: 206	I was shooting last night 1080p HQ 24 with 0 and -3 db gain and I noticed some noise on the videos. I had the iris fully open , manual everything. Is there any other possible setting that I may have missed? The image was well lit for what I put it through but I still saw noise when there should not have been.

May 26th, 2008, 06:20 PM	#13
Seun Osewa Major Player Join Date: Oct 2006 Location: West Africa Posts: 255	Oh for Christ sake he is using multiple ND filters and shooting at 1/500 shutter. Why won't his images be grainy when his ccd isn't getting enough light? Geez. Someone asks "why is my dead baby not breathing" and you say "check the temperature"?