Trouble with camcorder-- color values shift

9 Feb 2007 7:41 PM

Brian Siano

I was taping a community meeting this past week, and duiring the taping,
I'd noticed that the colors tended to shift a lot-- towards the
yellowish end of things. I wasn't sure if that was a problem with the
camera or the LCD display, but sure enough, when I transferred the
footage to my computer, many shots would shift to a yellowish huw very
abruptly. (Note: not _entirely_ yellow, but just yellowish.)

I was concerned that this might mean that my camcorder's gone bad (it's
a Sont TRV-740), but I found a website which discussed how shooting
under lots of fluorescent lights, with a lot of camera moves, throws off
the automatic white balance of many cameras. And both conditions fit my
situation. (The color shift didn't occur during the wild camera pans,
tho., but during relatively stable shots.)

Has anyone else enocuntered this problem? Or, has my hardware gone on
the fritz?

9 Feb 2007 7:47 PM

Gene E. Bloch

On 2/09/2007, Brian Siano posted this:
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> I was taping a community meeting this past week, and duiring the taping, I'd
> noticed that the colors tended to shift a lot-- towards the yellowish end of
> things. I wasn't sure if that was a problem with the camera or the LCD
> display, but sure enough, when I transferred the footage to my computer, many
> shots would shift to a yellowish huw very abruptly. (Note: not _entirely_
> yellow, but just yellowish.)
>
> I was concerned that this might mean that my camcorder's gone bad (it's a
> Sont TRV-740), but I found a website which discussed how shooting under lots
> of fluorescent lights, with a lot of camera moves, throws off the automatic
> white balance of many cameras. And both conditions fit my situation. (The
> color shift didn't occur during the wild camera pans, tho., but during
> relatively stable shots.)
>
> Has anyone else enocuntered this problem? Or, has my hardware gone on the
> fritz?

Sounds normal to me. If your camcorder has manual white balance or
white balance presets, use one of those options to keep it from
shifting. Choose the method that gives you the most pleasing results.

If it shifts under manual or a preset, then it *does* imply a camera
problem, but I suspect you'll be OK.

BTW, fluorescent lights flicker at 120 Hz, so it's possible that the
white balance can be fooled by how much of each pulse appears in each
frame, which might explain sudden shifts when not much movement is
happening (caution: I'm hypothesizing here!).

--
Gene E. Bloch (Gino)
letters617blochg3251
(replace the numbers by "at" and "dotcom")

9 Feb 2007 8:46 PM

PTravel

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"Brian Siano" <si***@mail.med.upenn.edu> wrote in message
news:eqiip8$bis$1@netnews.upenn.edu...
>I was taping a community meeting this past week, and duiring the taping,
>I'd noticed that the colors tended to shift a lot-- towards the yellowish
>end of things. I wasn't sure if that was a problem with the camera or the
>LCD display, but sure enough, when I transferred the footage to my
>computer, many shots would shift to a yellowish huw very abruptly. (Note:
>not _entirely_ yellow, but just yellowish.)
>
> I was concerned that this might mean that my camcorder's gone bad (it's a
> Sont TRV-740), but I found a website which discussed how shooting under
> lots of fluorescent lights, with a lot of camera moves, throws off the
> automatic white balance of many cameras. And both conditions fit my
> situation. (The color shift didn't occur during the wild camera pans,
> tho., but during relatively stable shots.)
>
> Has anyone else enocuntered this problem? Or, has my hardware gone on the
> fritz?

I've never had a problem with the color changing with camera moves under
flourescents. I have found, however, that where there was mixed light, i.e.
predominantly flourescent, but with incandescent lights in the room, or a
window that lets in outside light, the white balance can fluctuate rather
dramatically as the camera moves. In that instance, it would be best to
either do a manual color balance or lock down the color balance once the
camera has found something you like.

Show quoteHide quote

>

10 Feb 2007 7:03 PM

Brian Siano

PTravel wrote:

> I've never had a problem with the color changing with camera moves under
> flourescents. I have found, however, that where there was mixed light, i.e.
> predominantly flourescent, but with incandescent lights in the room, or a
> window that lets in outside light, the white balance can fluctuate rather
> dramatically as the camera moves. In that instance, it would be best to
> either do a manual color balance or lock down the color balance once the
> camera has found something you like.

Thanks to both you and Gene Bloch. Yep, the room was lit with
fluorescents and incandescents, and the frequent whip-panning to zoom in
on speakers did make for some abrupt change and shifts. Sadly, the
camera does not have manual white balance, which makes me want to
upgrade to a pro camera REAL soon. But it's something for me to watch
for in the future, and I don;t have to buy a new camera just yet.

12 Feb 2007 5:42 AM

Gene E. Bloch

On 2/10/2007, Brian Siano posted this:
Show quoteHide quote

> PTravel wrote:
>
>> I've never had a problem with the color changing with camera moves under
>> flourescents. I have found, however, that where there was mixed light,
>> i.e. predominantly flourescent, but with incandescent lights in the room,
>> or a window that lets in outside light, the white balance can fluctuate
>> rather dramatically as the camera moves. In that instance, it would be
>> best to either do a manual color balance or lock down the color balance
>> once the camera has found something you like.
>
> Thanks to both you and Gene Bloch. Yep, the room was lit with fluorescents
> and incandescents, and the frequent whip-panning to zoom in on speakers did
> make for some abrupt change and shifts. Sadly, the camera does not have
> manual white balance, which makes me want to upgrade to a pro camera REAL
> soon. But it's something for me to watch for in the future, and I don;t have
> to buy a new camera just yet.

How about preset white balance?

I thought *all* cameras had that :-)

Somewhere in the menus should be a place where you can set WB to auto,
daylight, incandescent, or fluorescent (or some sub- or superset of
those, perhaps with variants on the names).

If you have that, try each of the presets (the non-auto settings) and
see if one is reasonable - or choose the best of the unreasonable ones.

That would at lest prevent the shifting, making it easier to fix in
post (or at least one can hope so!).

--
Gene E. Bloch (Gino)
letters617blochg3251
(replace the numbers by "at" and "dotcom")