PD170 white balance problem

[Nancy Akin]

I recently purchased a new PD170. I've always had vx2000s before. The first time I used the PD170, I shot in a room with good lighting...flourescent lights, a very small amount of outside light coming in through the 95% closed blinds.

The white balance kept shifting from warm to cold. It didn't matter if I had it on manual or auto (remember, I'm familiar with the WB from my vx2000s). And it didn't matter if it was a moving or stationary shot. It was really, really weird.

It only did it in this one room. Not in any other room all day and not outside.

Here's a clip of what I'm talking about:

http://webpages.charter.net/nakin/WBtest.htm

I've shot in the room right next door to that one with my vx2000. It is an identical room....same size, same lighting, everything. And I never had this problem before.

Any ideas?

Thanks...Nancy

[Bob Hart]

Nancy.

You are most likely a more competent operator than myself however here goes anyway.

Did the whitelbalance shift occur during a single fixed setup or between takes?

Even with a fixed single setup, if there is movement going on in the room in a mixed light source environment, sources and directions of reflectance are going to change.

Vertical blinds 95% closed are also gong to behave like slot apertures and turn the room into one big camera obscura. Any movements of objects outside the room or motion such as the canopies of trees will be projected, in concentration but as mulitple indistinct images on the wall or objects opposite the window. This will form a source of reflected light which will be highly variable.

The PD170 has such good low light performance that these subtle changes will be evident.

You should either were possible, make all light sources a common colour temperature with correcting filter gels on windows or mask them off entirely and use all artificial light or use more powerful lights and reduce camera exposure (gain or iris) to drown the outdoors source.

Whitebalancing for each setup as an alternative may not work satisfactorily either.

I'm flying blind in this commentary as could not view the wmv clip, line speed is not the greatest at this end of the 30m of overhead copper pair.

Please do not pay much heed to my comments as I am not an industry professional.

[Bob Hart]

Deleted double post during edit when log-in timed out.

[Kurt August]

It also happened to me once, although I was using my trusted PD150. But also when shooting under tubelight using manual white balance. When suspecting something was odd (it was a rather slow but very constant color shifting), I turned the camera directly into the light and this sped up the process dramatically, so I was shure it wasn't just a hunch.

The only thing that helped, was resetting the camera with the pinhole button.

Luckily it was possible to redo the longer shots. Color correcting them would have been a pain.

I also remember having the problem with a cheaper Sony 3ccd camera.

So perhaps it really can be Sony/fluorescent thing. It always happened when shooting at night, so no issues with blinds, as Bob proposed. Although he has a very solid point.

Saw the movie now and yes that's what I'm talking about, although yours has it much more extreme, faster that is. It ain't good.

All the best, Kurt

[Nancy Akin]

Originally Posted by Bob Hart

Nancy.

Did the whitelbalance shift occur during a single fixed setup or between takes?

You should either were possible, make all light sources a common colour temperature with correcting filter gels on windows or mask them off entirely and use all artificial light or use more powerful lights and reduce camera exposure (gain or iris) to drown the outdoors source.

Whitebalancing for each setup as an alternative may not work satisfactorily either.

There were no "set-ups," so there were no "takes." It was a group of girls (bridesmaids/bride) getting ready. I had to go with what was there....recording live action. No bringing in lights....no masking windows....no set-ups of any kind. You just walk in and start shooting.

I've experimented with every kind of setting since then and can't get it to do it again. So I'm hoping against hope that it was a fluke!

[Nancy Akin]

Originally Posted by Kurt August

The only thing that helped, was resetting the camera with the pinhole button.

Luckily it was possible to redo the longer shots. Color correcting them would have been a pain.

I wondered about the resetting thing. Might give that a try anyway.

Since this was live recording, it was not possible to redo anything. And yes, the color correcting is going to be a MAJOR PAIN!!

I've tried and tried to reproduce the problem, but can't make it do that again. Hopefully, that was just a crazy, unexplainable one-time thing.

[Don Bloom]

Nancy,
if you have any custom presets be sure to write them down before you hit the reset button. Frankly I don't think that will solve the problem. This will sound goofy but is it possible that the was something else electrical (like curling irons or the like) plugged into that room that might have played havoc with the current? Long shot but I've never seen a 150 or 170 do anything like this. My 150 and 250 will take about 10 seconds to find the WB if its in auto. If its possible to duplicate the type of lighting you were in and the cam settings you might try to see if you can duplicate the problem when you're not under the gun of shooting a live event. Then you can slow things down a bit and see if you can figure out what caused it.
Don

[Nancy Akin]

Originally Posted by Don Bloom

Nancy,
if you have any custom presets be sure to write them down before you hit the reset button. Frankly I don't think that will solve the problem. This will sound goofy but is it possible that the was something else electrical (like curling irons or the like) plugged into that room that might have played havoc with the current? Long shot but I've never seen a 150 or 170 do anything like this. My 150 and 250 will take about 10 seconds to find the WB if its in auto. If its possible to duplicate the type of lighting you were in and the cam settings you might try to see if you can duplicate the problem when you're not under the gun of shooting a live event. Then you can slow things down a bit and see if you can figure out what caused it.
Don

I can duplicate the situation somewhat, but not exactly. The venue I shot this at is in another town. So going there just to duplicate this would not be possible. However, if it does it again, I might do just that. I might also call Sony, since this camera is less than 1 month old!

thanks...Nancy

[John Miller]

I had a similar issue with my PDX10 when recording some laboratory activity. All the lighting was standard fluorescent tubing.

I put it down to the following (which may be completely false but...)

The lighting isn't continuous - it strobes at line/mains frequency (or multiples thereof) and, most of the time, it doesn't affect us. (Personally, I'm sensitive to it and *hate* fluorescent lighting). I have often noticed on fast-moving or rotating objects that there appears to be a blue and brown component to shadows generated by the fluorescent light. Often I can see this if I just wave my hand from side-to-side with my fingers spread apart. If the shutter speed of the camcorder is slightly out of phase with the strobing frequency of the fluorescent lighting, then you could end up with the situation that the apparent color of the lighting cycles.


EDIT - Out of curiosity, I did a search after posting and found this:

http://photography-on-the.net/forum/...d.php?p=790596

There are some convincing photos showing the blue/brown effect. So I'm not going mad!

Also, Olympus have a (now expired) patent to detect and control this effect:

http://www.freepatentsonline.com/4595946.html


BTW - I'm also very sensitive to LEDs used on cars and radio towers - I can "tell" that they are strobing and not continuous. It's most distracting when a car in front has LED brake lights...

[Don Bloom]

Nancy,
wow, I didn't realize the camera is so young. I guess I would try to duplicate the problem first and then if you can make it happen again or get close I would call Sony and ask some questions.
It's funny I've been thinking back to my Sonys and can truthfully say I can't remember ever having this situation in the 5 years I've been using either 150s or a 250.
Please if you can figure out the problem ost it so we can all be aware of it. It COULD though just be one of those unexplained once in a lifetime things.
Cameras and computers sometimes have minds of their own.
Don

[Nancy Akin]

Originally Posted by Don Bloom

Nancy,
wow, I didn't realize the camera is so young. I guess I would try to duplicate the problem first and then if you can make it happen again or get close I would call Sony and ask some questions.
It's funny I've been thinking back to my Sonys and can truthfully say I can't remember ever having this situation in the 5 years I've been using either 150s or a 250.
Please if you can figure out the problem ost it so we can all be aware of it. It COULD though just be one of those unexplained once in a lifetime things.
Cameras and computers sometimes have minds of their own.
Don

If I figure it out, I'll definitely post it. But I've had these "once in a lifetime things" before....not with a camera, but definitely with my computer!!!

[Brandon Whiteside]

It's the cheapy flo lights that come from home depot that do this. The lights cycle at like 50hertz and that screws up the balance. Get some expensive lights, or put the camera on full auto, becuase then the camera compensates for the changes.

[Mike Rehmus]

If you live in the land of 60 cycle AC, the flourescent bulbs actually switch 120 times per second and are not normally detected by 30 frame/60 field per second video.

If you use a 30 fps video camera in 50 cycle land or vice-versa, a pulsing is visible but it isn't a color shift, just an amplitude shift.

I've shot a lot of video (classroom location, teaching actors to work with video) and have never seen strobing or other artifacts in spite of using standard overhead classroom flourescent lights part of the time. I've used PD-150, VX-1000, DSR-300, Panny 550 plus studio cameras. Strobing does not show up in any of the work and the studio is equipped with waveform monitors among the other measuring tools.

I've never had problems in mixed light either (other than a slightly ugly color balance). I'd guess the 170 has a problem that may be solved by a reset or a (first) call to Sony support and then maybe a trip to Sony.

[Hugh Garraway]

Nancy,

I too have a 170 and this week experienced, I think, the same problem you had taping a legal deposition. It was under fluorescent lighting and the iris was at about 2. I had let the camera set the iris then switched to manual. I also set wb manually before the deponent, wearing a white lab coat took her position. I also focused on her face then went to manual focus. The shutter speed was left in auto.

I didn't notice any color shifting on the LCD when I set up the shot but since the camera was static throughout the deposition I didn't pay close attention other than to make sure framing was correct from time to time.

When I played back the tape I noticed it cycling through changes in color.

A suggestion made to me was to force a smaller iris setting in order to increase the exposure time for each frame thereby 'catching' more of the lighting cycle fluctuation.

Like you, the shooting venue is in another city, and in my case, in a busy hospital conference room (radiology, & that opens up possibilities of interference from magnetic sources too) and I can't go back to replicate the conditions. I am going to go around to other fluorescent sources and try to find one that has the same problem and see if the forced iris setting helps. Also, I think I'll carry my own clamp-on lights with incandescent bulbs for future shoots like this. Will also shoot and closely monitor some test footage before beginning a deposition which is a one shot deal.

The link to your example is not working. Is it still available?


Thanks,

Hugh

[Bruce G. Cleveland]

Hi Nancy

I attempted to look at your link but it doesn't go anywhere. I am assuming it was temparary and is no longer valid??

Bruce