Running WB at DVinfo.net

Law Tyler · March 21st, 2004, 10:42 AM

Since the PD-150 and VX2000 has basically the same CCD as the DSR-250, perhaps somebody here has experienced this.

I shot a wedding recently, and in one scene the WB keeps "rotating" from blue to red and back to blue. You can see the (white) wall distinctly changing color, although the effect is less apparent on the people's face, thankfully.

It only went on for a minute or so, the rest of the hour taping was fine, although the problem clip was the only time I shot the people close to the wall.

I had this problem at first with my then new VX-2100 a few months ago, when I was shooting at 1/500th under fluorescent light, but this time it was 1/60th with the DSR-250, I checked and double-checked, had locked both my cameras into 1/60th months ago to avoid this problem.

The condition was the same, intense and numerous fluorescent lighting, very low ceiling, white walls all around. Middle size room. I wonder if it is the "reflections" that are out-of-frequency.

Any experience?

Mike Rehmus · March 21st, 2004, 02:02 PM

I've never seen anything change when WB is in manual. Was it a random or regular periodic shift?

Auto WB, however, can change as the scene in front of you changes. While you probably wouldn't notice the changes if you didn't have the white wall, it is reflecting the auto WB changes as the scene changes.

Want to test this? Aim at a white wall with WB in auto. Now move a yellow note pad up into the field of view. Large enough that it subtends say 1/3 of the view. You should see a shift on the white wall.

Light moves a 186,000 miles per second. Even the reflections change faster than I can see.

I'd guess the guests had on different colors? Or was there one of those mirror balls in operation?

Law Tyler · March 21st, 2004, 10:57 PM

Mike,

Thanks. The shift is a bit random, one to three seconds, one of them was even more. It probably did about 5 or 6 cycles only. I would say random.

No ATW. I double-checked the camera just now, it was off.

My standard shooting procedure -> lock shutter at 1/60th, manual gain control (at 0db unless), use auto aperture (have not started my zebra-ing habit yet) unless my pan view has extreme backlight, etc. First thing on scene set WB via a sheet of white 8.5x11, and eyeball it.

No, no mirror balls, just a plain white mid-size room, with lots of cheap home fluorescent lights, I thought one too many, must be several dozens.

This does not make sense, but then again I am not a video equipment expert... yet.

The previous case with the VX2100 and 1/500th shutter, made sense, but at 1/60th? Don't think there is anything else I can do to correct the problem regardless of the source.

Hmm..

Doug Okamoto · March 22nd, 2004, 09:53 AM

Hey Law,

Could it have been color shifting from the fluorescent lights? Those cheap every day kinds really shift alot, especially when they are about to go out. I do not like shooting in them but sometimes you got to do what you got to do! :)

It's unlikely but possibly could be from the paint on the wall? If it has any reflectivity, it would reflect different colors.

HTH anyway.

Law Tyler · March 22nd, 2004, 10:11 AM

Could be paint on the wall, I was panning left and right, but slowly. Probably combination of both.

Well, hope that never show up again. I used the footage. If they ask, I will blame it on the fluorescent lights.

Alan Christensen · March 23rd, 2004, 03:41 AM

I have seen this problem before and I don't understand what causes it. My problem used to occur with my VX2000 on a copy stand shooting straight down at a white sheet of paper. I would notice the cyclical shift in color as the camera tried to figure out how to automatically white balance. I don't think I ever saw the problem when in manual white balance mode, (after performing a manual white balance). I was under fluorescent lights at the time, so I wouldn't be surprised if they were the culprit. At the time the VX-2000 was in full auto mode.

March 21st, 2004, 10:42 AM	#1
Law Tyler Major Player Join Date: Dec 2003 Location: Plano, TX Posts: 204	Running WB Since the PD-150 and VX2000 has basically the same CCD as the DSR-250, perhaps somebody here has experienced this. I shot a wedding recently, and in one scene the WB keeps "rotating" from blue to red and back to blue. You can see the (white) wall distinctly changing color, although the effect is less apparent on the people's face, thankfully. It only went on for a minute or so, the rest of the hour taping was fine, although the problem clip was the only time I shot the people close to the wall. I had this problem at first with my then new VX-2100 a few months ago, when I was shooting at 1/500th under fluorescent light, but this time it was 1/60th with the DSR-250, I checked and double-checked, had locked both my cameras into 1/60th months ago to avoid this problem. The condition was the same, intense and numerous fluorescent lighting, very low ceiling, white walls all around. Middle size room. I wonder if it is the "reflections" that are out-of-frequency. Any experience?

March 21st, 2004, 02:02 PM	#2
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	I've never seen anything change when WB is in manual. Was it a random or regular periodic shift? Auto WB, however, can change as the scene in front of you changes. While you probably wouldn't notice the changes if you didn't have the white wall, it is reflecting the auto WB changes as the scene changes. Want to test this? Aim at a white wall with WB in auto. Now move a yellow note pad up into the field of view. Large enough that it subtends say 1/3 of the view. You should see a shift on the white wall. Light moves a 186,000 miles per second. Even the reflections change faster than I can see. I'd guess the guests had on different colors? Or was there one of those mirror balls in operation? __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

March 21st, 2004, 10:57 PM	#3
Law Tyler Major Player Join Date: Dec 2003 Location: Plano, TX Posts: 204	Mike, Thanks. The shift is a bit random, one to three seconds, one of them was even more. It probably did about 5 or 6 cycles only. I would say random. No ATW. I double-checked the camera just now, it was off. My standard shooting procedure -> lock shutter at 1/60th, manual gain control (at 0db unless), use auto aperture (have not started my zebra-ing habit yet) unless my pan view has extreme backlight, etc. First thing on scene set WB via a sheet of white 8.5x11, and eyeball it. No, no mirror balls, just a plain white mid-size room, with lots of cheap home fluorescent lights, I thought one too many, must be several dozens. This does not make sense, but then again I am not a video equipment expert... yet. The previous case with the VX2100 and 1/500th shutter, made sense, but at 1/60th? Don't think there is anything else I can do to correct the problem regardless of the source. Hmm..

March 22nd, 2004, 09:53 AM	#4
Doug Okamoto Regular Crew Join Date: Jan 2004 Location: Bellevue, Washington Posts: 145	Hey Law, Could it have been color shifting from the fluorescent lights? Those cheap every day kinds really shift alot, especially when they are about to go out. I do not like shooting in them but sometimes you got to do what you got to do! :) It's unlikely but possibly could be from the paint on the wall? If it has any reflectivity, it would reflect different colors. HTH anyway.

March 22nd, 2004, 10:11 AM	#5
Law Tyler Major Player Join Date: Dec 2003 Location: Plano, TX Posts: 204	Could be paint on the wall, I was panning left and right, but slowly. Probably combination of both. Well, hope that never show up again. I used the footage. If they ask, I will blame it on the fluorescent lights.

March 23rd, 2004, 03:41 AM	#6
Alan Christensen Regular Crew Join Date: Mar 2002 Location: California Posts: 139	I have seen this problem before and I don't understand what causes it. My problem used to occur with my VX2000 on a copy stand shooting straight down at a white sheet of paper. I would notice the cyclical shift in color as the camera tried to figure out how to automatically white balance. I don't think I ever saw the problem when in manual white balance mode, (after performing a manual white balance). I was under fluorescent lights at the time, so I wouldn't be surprised if they were the culprit. At the time the VX-2000 was in full auto mode.