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Old January 15th, 2002, 12:24 PM   #1
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exposure shift

Has anyone ever experienced a exposure shift while filming in full Manual mode?

I noticed it when there is a big change in the overall brightness of the scene and one time when it was really cold. I shot the sunrise and the exposure kept shifting to very blue and then back and forth.

Also the Frame Mode looks really bad with pans.

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Old January 15th, 2002, 12:33 PM   #2
Join Date: Sep 2001
Location: Tickfaw, LA
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Sure its not a lens flare?

It might be a lens flare or reflections in the lens elements or filters.

If you are panning fast in frame mode, that might be your problem.

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Nathan Gifford
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Old January 15th, 2002, 12:49 PM   #3
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Make sure you have your gain set to 0db or -3db or what ever you want it set too.

If you don't have your gain set to full Manual mode it will adjust the exposure.
Mark Chiocchi
Franklin Township, N.J.

DpsVelocity Editor
XL1S & GL1
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Old January 15th, 2002, 12:53 PM   #4
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Another factor could be white balance shifts when in auto-- sometimes they will look like an exposure change. I've seen this frequently in small theaters due to wierd lighting.

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Old January 15th, 2002, 05:17 PM   #5
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Thanks for the help on the exposure. I'm sure it wasn't a flare thing cause there wasn't much of a point source of light because the sun hadn't risen yet. I'll check the gain.

With the panning though, I tried some really slow pans and it looks (on a TV screen) like the image jumps backward, against the direction of the pan. It gets really exaggerated (of course) when it's faster. Is there any way to correct this in post (in FCP or After Effects)?
One more question (this is unrelated). Does the Sony dvx2000 have a bigger iris when wide open than the XL with standard 16x lens? Sony's pictures always seen brighter with very little light (and the same shutter speeds).
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Old January 16th, 2002, 02:43 AM   #6
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Join Date: Oct 2001
Location: Holland
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The problem that your pans look strange on your TV
might be because you are shooting in FRAME mode! In frame
mode all of the image is captured at the same time
(progressive scanning), with a slight quality loss in the
XL1(s). Since your TV is interlaced, it will show the
vertical lines that belong together apart of eachother
1/30th or 1/25th of a second. This creates a feeling
that something is wrong with the picture. If you look
at your PC/MAC monitor everything will look perfect!

The otherway around is true as well. If you shoot
in interlaced, your TV will show it perfectly. On your
computer monitor however, your seeing a sort of
striped image because the monitor cannot view the
image interlaced. It displays all the vertical lines at
the same time now and this will look weird because
they are supposed to be offset by again 1/30 or 1/25th
of a second (depending if your shooting NTSC or PAL).

If you shoot in FRAME mode and blow up to film it
should look great. Also if you create a progressive
DVD stream it should look good too on your TV
(your DVD player handles the problem then). Beamers
should be good too.

One other thing could be that your optical image
stabilizer in the XL1(s)'s lense gets in the way?
If your on a tripod for example you should disable
it. Perhaps this might be a thing that caused your
pan troubles. An easy way to check this is to look
at the footage on your computer. If it looks okay
there, then there is a presentation issue (probably
the interlacing vs. frame issue I talked about above).
If it still looks bad the problems was when you where
shooting it (i'm suspecting the image stabilizer here)...

Hope this helps some.

Rob Lohman, visuar@iname.com
DV Info Wrangler & RED Code Chef

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