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Ligh streaking with 3ccd camera.

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Josh Munson
Ligh streaking with 3ccd camera.
on Aug 15, 2009 at 3:03:23 am

I went to the beach recently and brought along my little Panasonic PF-GS320. I noticed that all of the footage shot in low light had long vertical streaks wherever a bright light was present. I'm wondering why this is and if there anyway to reduce this in the future. I know there is some streaking like that, so I've heard, due to the sensors. If anyone could shed more light or help me out it would be greatly appreciated.
Thanks!
-Josh


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Steven Bradford
Re: Ligh streaking with 3ccd camera.
on Aug 16, 2009 at 2:28:04 am

There's not a lot you can do, other than to get a better camera. And by better, I mean quite a bit more expensive than you're probably wiling to pay--this is one of the big dividing lines between pro and consumer gear.

The best I can think of is try to avoid having the lights right at the top of the frame edge. In some cameras this seems to result in the biggest streaks. Setting to a higher speed shutter will help, but of course, this will negate your ability to shoot in low light.

What's happening is that the sensor wells where the light hits are overloaded and the voltages cascade down the sensor. It's almost as if they're overflowing with photons. This was a big problem with the first broadcast grade expensive news cameras with CCD chips 20+ years ago. It was removed by using different chip designs.

Over time I'm sure we'll see this disappear from low end cameras too as the cost of sensors drop.

Steven Bradford
http://www.3dstereomedia.com 3D company I've worked with since 1990
http://www.seanet.com/~bradford/ my personal home page, find my greenscreen page there.
http://www.seattlefilminstitute.com the school I teach at.


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Josh Munson
Re: Ligh streaking with 3ccd camera.
on Aug 16, 2009 at 2:42:12 am

Thanks, that was what I was basically assuming. I'll have to wait to I'm in the market for a new camera to fix this I suppose. I appreciate you explaining everything and helping me out.
-Josh


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Todd Terry
Re: Ligh streaking with 3ccd camera.
on Aug 16, 2009 at 4:39:57 am

FWIW... even with very high-end CCD cameras you can see this issue crop up, espcially with very bright point light sources in very dark scenes. It's one of those annoyances that may be hard to eliminate completely when using a CCD camera in a very particular lighting setup like that... no matter how much money you throw at it.

Best bet for now (and later) is simply just to avoid whenever you can point light sources within the frame that you know are going to bloom to more than 100% luminance.


T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com






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Josh Munson
Re: Ligh streaking with 3ccd camera.
on Aug 16, 2009 at 4:59:59 pm

So there isn't too much I can do but be creative and work around while shooting I suppose. What about other types of cameras? Do cameras using CMOS have this problem as well?


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Steven Bradford
Re: Ligh streaking with 3ccd camera.
on Aug 22, 2009 at 6:19:13 pm

I'm fairly certain that CMOS sensors don't have trouble with vertical smear at all. At least that's what a quick google confirms.

Steven Bradford
http://www.3dstereomedia.com 3D company I've worked with since 1990
http://www.seanet.com/~bradford/ my personal home page, find my greenscreen page there.
http://www.seattlefilminstitute.com the school I teach at.


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Tony Stampalia
Re: Ligh streaking with 3ccd camera.
on Aug 17, 2009 at 5:30:04 pm

Star filter. At least make it look pretty.


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