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09-16-2010, 02:51 PM   #1
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K-7 -> Vertical banding in low light black and white video

I have made some video in low light today with my K-7. From a Dutch artist Charlie Dée. I did this before and had some soso video quality because of high level of noise. Now with the new firmware I notice havy banding? Anyone who knows where its coming from or having the same experiences?

Shot today and is probably iso3200 or a like, made with either DA*55 or FA*85
[YT]http://www.youtube.com/watch?v=eK1LvcIqC9Q[/YT]


This what I recorded some months ago before the new firmware with the DA55:
[YT]http://www.youtube.com/watch?v=QqBVouXikUc[/YT]

I would like some input from you guys.


To Adam, this is a dubble post, don't know if it is allowed, but the problem seems to me quit big so some attention would be nice.

09-16-2010, 04:07 PM   #2
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Second video is good.
The first one looks like heavy compression taking place. I am failing to see vertical banding how ever, could just be me.

Cheers, Mike.
09-16-2010, 07:05 PM   #3
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I see the banding just to the left of her head. Can you see that if you take a picture of a blank wall at iso 6400?
09-16-2010, 07:32 PM   #4
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I see a lot of pretty annoying flickering on the first video. Might have something to do with your lighting.

09-16-2010, 11:25 PM   #5
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QuoteOriginally posted by pasipasi Quote
I see a lot of pretty annoying flickering on the first video. ...
I saw that too. Thought it might be a ceiling fan casting moving shadows.

Last edited by abmj; 09-16-2010 at 11:58 PM.
09-17-2010, 12:46 AM   #6
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QuoteOriginally posted by RonHendriks1966 Quote
I did this before and had some soso video quality because of high level of noise. Now with the new firmware I notice havy banding? Anyone who knows where its coming from or having the same experiences?
I'd find it hard to beleive anyone would care about banding considering the overwhelming light flickering in the scene.
Sorry to say, but banding is the least of your problems in that first video tbh.

FTR. there are situations in cinematography where intermitent lighting is complimentary. But this isn't one of them I'm afraid

Great singer btw!
09-17-2010, 03:49 AM   #7
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Looks like the camera is at its highest sensitivity and the ACG feedback on the signal is too strong in high light areas, generating a sort of oscillation.
If the happened after firmware upgrade, it is a software (DSP?) problem.

The probably only solution is to work with more light and faster lenses.... not that you can...

You also have a hot pixel, in the lower left corner.

- Bert

Last edited by bymy141; 09-17-2010 at 03:54 AM.
09-17-2010, 04:23 AM   #8
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In the first video I say it’s the fluorescent lights at 60hz vs. whatever
frames per second you are shooting at. I've seen that plenty of times
with camcorders.

09-17-2010, 04:56 AM   #9
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QuoteOriginally posted by PinarelloOnly Quote
In the first video I say it’s the fluorescent lights at 60hz vs. whatever
frames per second you are shooting at. I've seen that plenty of times
with camcorders.
The OP lives in the Netherlands. Line frequency is 50Hz in Europe.
That will give a 100Hz flicker with fluorescent lights, which is much faster than the flickering (at a non constant rate) in the video.

- Bert
09-17-2010, 07:44 AM   #10
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QuoteOriginally posted by bymy141 Quote
The OP lives in the Netherlands. Line frequency is 50Hz in Europe.
That will give a 100Hz flicker with fluorescent lights, which is much faster than the flickering (at a non constant rate) in the video.

- Bert
I do not know how you got to 100hz but it still is the lighting that is doing it.
If a hertz is one cycle isn't still 50hz then? Europe or not you still have to slow
down the shutter with fuorecent lighting, right?

Besides in the first video anyway it's horizontal banding I do not see any vertical anything.

Last edited by PinarelloOnly; 09-17-2010 at 07:50 AM.
09-17-2010, 09:12 AM   #11
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Well the light is one thing. I did not have any control over what light there was. The one everyone is talking about is a dimm light anyway. Don't know what frequentie or what shutter to use, never experienced it before.

Some of the banding is not to see in the movie that youtube is showing. So there is some works don in the process of youtube after that I uploaded my right out of the K-7 coming clip. It's the K-7 so it is a 30 frames movie.

I also don some pictures and they are iso3200 and a shuttertime of 1/30 to 1/50 at f1.4 so it is most likely that the vid also is iso3200.

Maybe someone can check this at home if this is a new thing from the new Firmware or just something of my camera?
09-17-2010, 10:18 AM   #12
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QuoteOriginally posted by PinarelloOnly Quote
I do not know how you got to 100hz but it still is the lighting that is doing it.
If a hertz is one cycle isn't still 50hz then? Europe or not you still have to slow
down the shutter with fuorecent lighting, right?

Besides in the first video anyway it's horizontal banding I do not see any vertical anything.
I think you are refering to the stroboscopic effect of filming objects in fluroresent light, due to the interference of the shutter speed and the lamp light flicker ferquency.
That can normally give fluctuating lighting effects, banding off images captured off another screen etc.

If that would be the case here, the effect would be visible for all of the picture, wouldn't it?
Not just some high light area's, and the pattern would be a repeating pattern.
Both are not the case here, I've looked at the video some more, the pattern changes over time.

I still don't think it is light interference.
Also, the K-7 captures video at 30 fps, interfering with 2 x 50Hz pulsing light source would create a wave like flicker frequency of 1/30 second.

- Bert
09-17-2010, 12:02 PM   #13
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[IMG][/IMG]

This is from another video, a screenshot and a cut out because off the tinypic limit. So you can see what I'm talking about.
09-17-2010, 07:36 PM   #14
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Yeah dude I see what you're talking about. To be honest I think that's fixed pattern noise. Basically the bias frame the camera uses is not 100% accurate, I have the same problem with my K-7 and shots over ISO 2000. I'm not sure what the best solution is right now, especially for video.

I might take a hack at implementing a fixed pattern noise removal tool one day for DNG files, but this may have been done before.

BTW, the higher you expose, the less noticeable the fixed pattern noise. It's just a bias, so increasing the light on the sensor essentially decreases the overall visual perception of the noise (note, that specific noise, not all noise). Try overexposing 2/3 stop and then bringing it back down if need be in video editing software like virtualdub.
09-17-2010, 11:41 PM   #15
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QuoteOriginally posted by jeffshaddix Quote
Yeah dude I see what you're talking about. To be honest I think that's fixed pattern noise. Basically the bias frame the camera uses is not 100% accurate, I have the same problem with my K-7 and shots over ISO 2000. I'm not sure what the best solution is right now, especially for video.

I might take a hack at implementing a fixed pattern noise removal tool one day for DNG files, but this may have been done before.

BTW, the higher you expose, the less noticeable the fixed pattern noise. It's just a bias, so increasing the light on the sensor essentially decreases the overall visual perception of the noise (note, that specific noise, not all noise). Try overexposing 2/3 stop and then bringing it back down if need be in video editing software like virtualdub.
Could it be that with the new firmware the longest shuttertime wend up, Because I did not experienced this before?
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