Is this normal? at DVinfo.net

George Palmier · July 4th, 2006, 11:15 PM

Hi everyone. I am quite new to professional cameras. When I shoot during the night with the Hd100 and there is a source of light in the frame, a vertical stripe of light appears from that source. Is this a normal thing to happen or is there any setting to eliminate this problem? Hope I explained myself good enough.

Stephan Ahonen · July 5th, 2006, 06:42 AM

That is a CCD flare, and is a byproduct of the way that CCDs scan. I know at least one HD100 has had some serious flare issues, so whether what you're seeing is "normal" depends on how big the flare is. It also depends on how bright the light source is. Frame grabs would be helpful.

Mark Silva · July 5th, 2006, 11:21 AM

If you close the iris down a little the streak becomes a star and looks much nicer.

Thats the way to deal with it.

George Palmier · July 5th, 2006, 11:46 AM

But how can you do that when you are filming with only available light and gain at 18db?!!

Stephan Ahonen · July 6th, 2006, 05:22 AM

At 18dB your picture is so grainy and fuzzy that a little bit of flare (or even a lot of flare) is the least of your worries. What are you shooting that you need so much gain? Lowering it will definitely reduce the problem.

George Palmier · July 6th, 2006, 08:43 AM

I was shooting a street during the night. This flare effect happened most when the street lights were against the dark sky. Ok maybe not really a must to set gain to 18db but definately I couldn't close the iris as suggested earlier in this thread. Thanks for answering to my problem

Steve Oakley · July 6th, 2006, 12:16 PM

a strong vertical line that comes from a light source is called Vertical Smear, its not flare. it has to do with the charge in the individual pixel overflowing into its neighbors above and below. its a charactoristic of CCD IT devices. Sony broadcast cameras usually have a rating for this at -120db or something, which means you won't ever see it except in the most extreme conditions. there are ways of taming the overflow charge, and basically the more expensive the CCD chip, the less it has the problem because they can afford to add the charactorics ( and perhaps some components ) to better deal with the overflow.

STeve Oakley

George Palmier · July 6th, 2006, 12:28 PM

Thanks for your deep explanation steve. But is there something one can do to eliminate or at least lower this vertical smear?

Adam Oas · July 6th, 2006, 12:42 PM

Frame so that the lights are not in the shot
Flag or Gaff off the direct light sources,
Stop the lens down / Add more light,
Buy a more expensive camera with better CCDs

Jack Walker · July 6th, 2006, 12:48 PM

You also might try a filter on the lens.
Also, you might try a piece of net over the lens.

Might end up with beautiful stars or twinkly lights instead of streaks.

George Palmier · July 6th, 2006, 01:01 PM

What filter can be used to reduce vertical smear?

Jack Walker · July 6th, 2006, 02:38 PM

Any filter that would break up the light might do something desireable. Perhaps a star filter. Perhaps one of the smoothing filters that has a grid imbedded, or some other. I think this would be something to just try if you have some filters. Perhaps someone has specific experience that applies. I have just notice on my SD cameras that different filters affect highlights and "streaks" in different ways.

Tim Dashwood · July 6th, 2006, 02:52 PM

Quote:

Originally Posted by George Palmier

What filter can be used to reduce vertical smear?

I've used a 1/4 black promist before and it seemed to work well.

July 4th, 2006, 11:15 PM	#1
George Palmier Regular Crew Join Date: Mar 2006 Location: Malta Posts: 96	Is this normal? Hi everyone. I am quite new to professional cameras. When I shoot during the night with the Hd100 and there is a source of light in the frame, a vertical stripe of light appears from that source. Is this a normal thing to happen or is there any setting to eliminate this problem? Hope I explained myself good enough.

July 5th, 2006, 06:42 AM	#2
Stephan Ahonen Major Player Join Date: Apr 2005 Posts: 512	That is a CCD flare, and is a byproduct of the way that CCDs scan. I know at least one HD100 has had some serious flare issues, so whether what you're seeing is "normal" depends on how big the flare is. It also depends on how bright the light source is. Frame grabs would be helpful.

July 5th, 2006, 11:21 AM	#3
Mark Silva Major Player Join Date: Apr 2006 Location: Pacific NW Posts: 431	If you close the iris down a little the streak becomes a star and looks much nicer. Thats the way to deal with it.

July 5th, 2006, 11:46 AM	#4
George Palmier Regular Crew Join Date: Mar 2006 Location: Malta Posts: 96	But how can you do that when you are filming with only available light and gain at 18db?!!

July 6th, 2006, 05:22 AM	#5
Stephan Ahonen Major Player Join Date: Apr 2005 Posts: 512	At 18dB your picture is so grainy and fuzzy that a little bit of flare (or even a lot of flare) is the least of your worries. What are you shooting that you need so much gain? Lowering it will definitely reduce the problem.

July 6th, 2006, 08:43 AM	#6
George Palmier Regular Crew Join Date: Mar 2006 Location: Malta Posts: 96	I was shooting a street during the night. This flare effect happened most when the street lights were against the dark sky. Ok maybe not really a must to set gain to 18db but definately I couldn't close the iris as suggested earlier in this thread. Thanks for answering to my problem

July 6th, 2006, 12:16 PM	#7
Steve Oakley Trustee Join Date: Apr 2006 Location: United States Posts: 1,158	a strong vertical line that comes from a light source is called Vertical Smear, its not flare. it has to do with the charge in the individual pixel overflowing into its neighbors above and below. its a charactoristic of CCD IT devices. Sony broadcast cameras usually have a rating for this at -120db or something, which means you won't ever see it except in the most extreme conditions. there are ways of taming the overflow charge, and basically the more expensive the CCD chip, the less it has the problem because they can afford to add the charactorics ( and perhaps some components ) to better deal with the overflow. STeve Oakley

July 6th, 2006, 12:28 PM	#8
George Palmier Regular Crew Join Date: Mar 2006 Location: Malta Posts: 96	Thanks for your deep explanation steve. But is there something one can do to eliminate or at least lower this vertical smear?

July 6th, 2006, 12:42 PM	#9
Adam Oas Regular Crew Join Date: Jun 2006 Location: Fort Worth TX Posts: 69	Frame so that the lights are not in the shot Flag or Gaff off the direct light sources, Stop the lens down / Add more light, Buy a more expensive camera with better CCDs

July 6th, 2006, 12:48 PM	#10
Jack Walker Trustee Join Date: Jun 2006 Location: Burbank Posts: 1,811	You also might try a filter on the lens. Also, you might try a piece of net over the lens. Might end up with beautiful stars or twinkly lights instead of streaks.

July 6th, 2006, 01:01 PM	#11
George Palmier Regular Crew Join Date: Mar 2006 Location: Malta Posts: 96	What filter can be used to reduce vertical smear?

July 6th, 2006, 02:38 PM	#12
Jack Walker Trustee Join Date: Jun 2006 Location: Burbank Posts: 1,811	Any filter that would break up the light might do something desireable. Perhaps a star filter. Perhaps one of the smoothing filters that has a grid imbedded, or some other. I think this would be something to just try if you have some filters. Perhaps someone has specific experience that applies. I have just notice on my SD cameras that different filters affect highlights and "streaks" in different ways.