GL2 Exposure changes when panning from bright to low light at DVinfo.net

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Canon GL Series DV Camcorders
Canon GL2, GL1 and PAL versions XM2, XM1.


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Old March 18th, 2003, 08:53 PM   #1
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GL2 Exposure changes when panning from bright to low light

Probably a stupid question, but I recently was shooting a few trains in a train yard during a sunset. I was in FULL MANUAL mode on the GL2 and started panning from a woods shot toward the cloudbreak in the sky shich contained the sunset. Keep in mind this is all on the horizon. When going from the dark clouds to the bright sunset, the exposure changed dramatically and darkened the clouds beyond belief. I was under the impression with full MANUAL mode that the exposure should not change, no matter what the light source. Now I know there is an "exposure lock" option, but that seems to only be available in the Shutter/Aperture settings. Any ideas? Am I an idiot to think that this should not happen? I can post a vid if someone can host. Thanks again,

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Old March 18th, 2003, 11:27 PM   #2
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Michael,
Aside from judging the image in the viewfinder, did you actually see the iris and shutter speed figures change in the viewfinder display?
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Old March 19th, 2003, 05:21 AM   #3
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I'm not exactly sure I'm following the course of your events. But if you are in manual you should notice the scene get lighter or darker if the light value in you scene changes. This can be due to panning (as you did) or a change in lighting (sun moving behind clouds etc.). The camera uses (in an auto or program mode) the aperture and or shutter speed to keep the relative light value reaching your chip (CCD) the same level. By controlling the aperture and shutter speed the camera can adjust the exposure to maintain a relative level of exposure during pans and changing light conditions.

Putting the camera in manual and setting proper exposure for a specific scene and then panning will usually cause the exposure to change (scene gets too light or too dark) because of the inability of the camera to automatically compensate for light level changes.
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Old March 19th, 2003, 09:08 AM   #4
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Let me review the tape tonight and see if the shutter/aperture changes when the scene became lighter. Anyone able to host a clip? Or can I somehow upload it on the forum?

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Old March 19th, 2003, 09:24 AM   #5
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Did you happen to hear a click and see "ND" come on in the display? I haven't checked myself, but it's possible that the ND filter will get automatically activated (and I kind of think I've seen it happen) even in full manual mode when you go to extremely bright conditions that the camera feels it can't handle.

Anyone else confirm this, or have seen an entry in the manual to indicate this could happen? I know I've seen the ND filter switch on automatically before in bright sun, but I forget if I was in full manual or not.
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Old March 19th, 2003, 10:13 AM   #6
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make sure that your gain is not in auto mode.

I've been burnt by that in the past more than once on XL1 and GL1.

On my XL1, I put a dab of hotglue to keep the knob locked at 0 gain.
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Old March 19th, 2003, 10:22 AM   #7
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Brian,
I don't think the ND filter can self-engage, although it's easy to inadvertently press its button.

Adrian, the gain operates differently on the GL2 than on the XL1/XL1S. There is no physical dial, but rather a digital setting that appears when Manual mode is engaged. (There are also color gain sliders buried in a menu.)
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Old April 1st, 2003, 11:12 AM   #8
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The GL2 in Auto Mode (that's what you said right?) will always adjust the exposure as you pan from one light level to another. That's why it has the Manual capability, to lock in the exposure you want. The key is to "plan your pan". Before you start rolling, pan to the sunlight and set your exposure, then pan to the clouds and set again. Repeat steps until you find a middle ground that looks good all the way through the pan.

No, the ND Filter will not self-engage, however it will flash on the viewfinder when it thinks you SHOULD be using it and aren't.
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