Noise in dark greens and blacks at DVinfo.net

Graeme Fullick · January 7th, 2009, 07:17 PM

Guys,

I am having real trouble getting my EX1 to produce clean blacks and dark greens, They are almost always full of really objectionable noise, though the rest of the picture looks great. Even if I shoot in quite reasonable light the problem presists. At first I thought that I had just set up a picture profile that caused too much noise from one channel, but I have now been testing my camera with no picture profile (yes I know that it is Standard 3), with Doug Jensens "Doug 1" and a few others - always with the same result. A parallel test with a Canon HV20 in the same conditions produces rock solid colours. Is it possible that there is an issue with my cameras gain section, or is there some setting that I have inadvertantly switched that might cause this problem?

Any help here is much appreciated as it is driving me bananas.

Perrone Ford · January 7th, 2009, 07:43 PM

Two questions:

1. What is: "...quite reasonable light"? How much light are you talking?

2. What is your gain set to?

Is it possible for you to post a still image of what you're seeing as well as your camera settings (iris, gain, light level in lux/FC)?

Graeme Fullick · January 7th, 2009, 07:59 PM

Perrone,

THanks for the quick reply.

Reasonable light is a typical dull overcast day at midday - can't tell you what lux that is, but auto iris was giving me about F4 with no ND filters, and centre light meter was about 38% on the dark green jacket that I was testing. Gain was set at -3dB.

The Canon HV20 on the same scene produced a rock solid green with no noise.

I have subsequently done an iris closed test at both 0dB and -3db - both have subtle green noise spots in the picture. My repair agent tells me that at 0dB there should be no noise for an iris closed test - so I now suspect a problem with either the CMOS block or the processor board. Either way it looks like a trip to the repair agent.

Perrone Ford · January 7th, 2009, 08:37 PM

By chance, have you done a black balance on the camera to tell it what "black" actually should be?

Robert Bale · January 7th, 2009, 09:44 PM

Quote:

Originally Posted by Perrone Ford

By chance, have you done a black balance on the camera to tell it what "black" actually should be?

So, a Black Balance, what was the best way to get a good result ?

Perrone Ford · January 7th, 2009, 10:07 PM

Not sure I understand your question.

Robert Bale · January 7th, 2009, 10:20 PM

Quote:

Originally Posted by Perrone Ford

Not sure I understand your question.

Sorry, what it the best way to set it, do i do like i would manual white balance?

Perrone Ford · January 7th, 2009, 10:31 PM

Yea, close the lens cover and the iris. On the EX1 it's apparently in the maintainance menu. I've not done it, and I need to.

Graeme Fullick · January 7th, 2009, 10:50 PM

Perrone,

The authorised Sony repair agent thinks that what I have is far more significant than a black balance. As it is only the greens and blacks (which look brownish from noise) that seem affected. When I do a close lens 0 gain test I see green noise flecks in the picture that should be black.

Perrone Ford · January 7th, 2009, 11:02 PM

Well, let them have a look by all means, and report back what they find. This one is curious...

January 7th, 2009, 07:17 PM	#1
Graeme Fullick Major Player Join Date: Mar 2005 Location: Newcastle, Australia Posts: 337	Noise in dark greens and blacks Guys, I am having real trouble getting my EX1 to produce clean blacks and dark greens, They are almost always full of really objectionable noise, though the rest of the picture looks great. Even if I shoot in quite reasonable light the problem presists. At first I thought that I had just set up a picture profile that caused too much noise from one channel, but I have now been testing my camera with no picture profile (yes I know that it is Standard 3), with Doug Jensens "Doug 1" and a few others - always with the same result. A parallel test with a Canon HV20 in the same conditions produces rock solid colours. Is it possible that there is an issue with my cameras gain section, or is there some setting that I have inadvertantly switched that might cause this problem? Any help here is much appreciated as it is driving me bananas. __________________ Graeme

January 7th, 2009, 07:43 PM	#2
Perrone Ford Inner Circle Join Date: Nov 2006 Location: Tallahassee, FL Posts: 4,100	Two questions: 1. What is: "...quite reasonable light"? How much light are you talking? 2. What is your gain set to? Is it possible for you to post a still image of what you're seeing as well as your camera settings (iris, gain, light level in lux/FC)? __________________ DVX100, PMW-EX1, Canon 550D, FigRig, Dell Octocore, Avid MC4/5, MB Looks, RedCineX, Matrox MX02 mini, GTech RAID, Edirol R-4, Senn. G2 Evo, Countryman, Moles and Lowels.

January 7th, 2009, 07:59 PM	#3
Graeme Fullick Major Player Join Date: Mar 2005 Location: Newcastle, Australia Posts: 337	Perrone, THanks for the quick reply. Reasonable light is a typical dull overcast day at midday - can't tell you what lux that is, but auto iris was giving me about F4 with no ND filters, and centre light meter was about 38% on the dark green jacket that I was testing. Gain was set at -3dB. The Canon HV20 on the same scene produced a rock solid green with no noise. I have subsequently done an iris closed test at both 0dB and -3db - both have subtle green noise spots in the picture. My repair agent tells me that at 0dB there should be no noise for an iris closed test - so I now suspect a problem with either the CMOS block or the processor board. Either way it looks like a trip to the repair agent. __________________ Graeme

January 7th, 2009, 08:37 PM	#4
Perrone Ford Inner Circle Join Date: Nov 2006 Location: Tallahassee, FL Posts: 4,100	By chance, have you done a black balance on the camera to tell it what "black" actually should be? __________________ DVX100, PMW-EX1, Canon 550D, FigRig, Dell Octocore, Avid MC4/5, MB Looks, RedCineX, Matrox MX02 mini, GTech RAID, Edirol R-4, Senn. G2 Evo, Countryman, Moles and Lowels.

January 7th, 2009, 10:07 PM	#6
Perrone Ford Inner Circle Join Date: Nov 2006 Location: Tallahassee, FL Posts: 4,100	Not sure I understand your question. __________________ DVX100, PMW-EX1, Canon 550D, FigRig, Dell Octocore, Avid MC4/5, MB Looks, RedCineX, Matrox MX02 mini, GTech RAID, Edirol R-4, Senn. G2 Evo, Countryman, Moles and Lowels.

January 7th, 2009, 10:31 PM	#8
Perrone Ford Inner Circle Join Date: Nov 2006 Location: Tallahassee, FL Posts: 4,100	Yea, close the lens cover and the iris. On the EX1 it's apparently in the maintainance menu. I've not done it, and I need to. __________________ DVX100, PMW-EX1, Canon 550D, FigRig, Dell Octocore, Avid MC4/5, MB Looks, RedCineX, Matrox MX02 mini, GTech RAID, Edirol R-4, Senn. G2 Evo, Countryman, Moles and Lowels.

January 7th, 2009, 10:50 PM	#9
Graeme Fullick Major Player Join Date: Mar 2005 Location: Newcastle, Australia Posts: 337	Perrone, The authorised Sony repair agent thinks that what I have is far more significant than a black balance. As it is only the greens and blacks (which look brownish from noise) that seem affected. When I do a close lens 0 gain test I see green noise flecks in the picture that should be black. __________________ Graeme

January 7th, 2009, 11:02 PM	#10
Perrone Ford Inner Circle Join Date: Nov 2006 Location: Tallahassee, FL Posts: 4,100	Well, let them have a look by all means, and report back what they find. This one is curious... __________________ DVX100, PMW-EX1, Canon 550D, FigRig, Dell Octocore, Avid MC4/5, MB Looks, RedCineX, Matrox MX02 mini, GTech RAID, Edirol R-4, Senn. G2 Evo, Countryman, Moles and Lowels.