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


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Old May 23rd, 2003, 12:11 AM   #31
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I think Bud's "pulsing" problem was the same problem. His pulsing probably related to his use of the digital zoom.

Hard to say about the Sony's problem. It sure looked like the same problem (on an enormous screen). I really doubt that it was a hood problem, though. This was an experienced camera operator not likely to make such a boo boo.

I actually use the WD58 adapter on my GL2 most of the time and have yet to encounter the problem with it mounted. Not saying that the adapter is the prophlactic, just that I haven't experienced it.
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Old May 23rd, 2003, 12:44 AM   #32
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Just a thought Ken

How close were the serial numbers on the pair of GL2's you've had this issue with.

I checked my GL1 for this issue, and am not seeing it.
Have any clips or photos you want to show for a visual descripton?
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Old May 23rd, 2003, 01:09 AM   #33
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Couldn't say, Dan. I didn't record the s/n of the first GL2 that I exchanged for the second. I'd bet that they may have been close numbers, as both came from the same dealer within days.

Day's shot reflects the problem pretty much dead-on.

Aaron and Randy Wisman (XM2) have also encountered this. I think Jeff Donald's supposition of slight variations in lens manufacture hits the nail on the head. Apparently the GL2/XM2's lens' design is such that it's just on the fringe of some boundary optical property. One micrometer of grind variation too much and...
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Old May 23rd, 2003, 06:58 AM   #34
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I wasn't using digital zoom at this time!

So what would be your suggestion ? return or keep ?

Thanks to everybody.
Dany
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Old May 23rd, 2003, 11:25 AM   #35
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I can't tell you what you should do, Dany. I can only tell you the decision I made long ago and why I made it, which I did above. It's just not a very big issue to me.
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Old May 23rd, 2003, 10:13 PM   #36
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If the origin of this "imaging bug" is of a mechanical nature, obviously a lens/camera redesign would be required to eliminate the problem. There's another intriguing possibility...what if the problem was caused by limitations of the camera's current ROM drivers and if that's the case, wouldn't Canon be able to fix it with a drivers/software update?. Since this bug shows up under unique filming situations, not likely to be encountered or noticed under most filming conditions, the only thing that would move Canon to come up with a fix would be if they heard from a lot of their GL2 customers.
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Old May 24th, 2003, 02:46 AM   #37
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I bought my XM2 almost a month ago.

I've found the problem of "key hole" on my camcorder too.
The factory continues to make so priced units with this "bug".
I don't know if they will do something to solve the problem considering that mine is a very new machine.
Is it possible that they haven't yet noted the problem?
I don’t think so.

Anyway, I hope that all these reports from us will lead somebody at the factory to do something.

I can say that at the beginning I worried a lot about this shortcoming.
Now I’m learning to manage it.
In my experience, the “key hole” effect is mostly visible in low light and in particular conditions.
The effect is more noticeable operating the zoom.
It seems that the worst point is in the middle of zoom range.
I've tried to modify the "key hole" in manual mode but no control has effect in it except the zoom.

On the other hand, in most cases the machine makes really outstanding beautiful images (even good photos!)
Colours are never excessive but well saturated and balanced.
Images have a good sharpness and noise is almost invisible even in reasonable low light.

Hope this may help.
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Old May 24th, 2003, 01:30 PM   #38
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I don't know...I guess I've been listening to this discussion so long that I'm getting crabby...The so called keyhole problem is nothing more than an "uneveness of field" issue, which effects every zoom lens on the planet...(make that every lens, period). The gl2 as well as gl1 and and xl1s will all exhibit this problem in varying degrees due to the "longer than industry standard" zoom lengths. While we would all like a perfect zoom lens with a fisheye to moon crater zoom range with no vignetting (let's get the term right) or chromatic aberation. I'd also like a lens would bring us (god help us) peace without honor....

But it ain't gonna happen. There is a reason that a good cine zoom lens costs upwards of $20,000, and even then, I guarantee you if you pushed the film 3 stops (equivalent of 18db gain) and then did a rack zoom, you would find some unevenness of field visible in the footage.

The gl2 produces amazing results for a camera with a 20x zoom (oops I guess it's the only one)...I'm not trying to be a cheerleader when I say that perhaps we shouldn't be so amazed at its shortcomings as we should at the fact that the zoom is as good as it is. Canon engineers have pulled off a miracle zoom in my opinion...look at the size of the thing and then compare it to the zoom on the xl1s...(the lens alone is almost as big as the gl2).

I've been in commercial photography for almost 20 years, and I've never seen a perfect lens yet...especially a zoom. All systems have their limitations, and its one of the exciting things about being in this biz...learning what the limitations are, and then figuring out ways to succeed anyway...

This discussion is useful. Hopefully it encourages Canon to continue to advance their technology to produce even better cameras....but the point that is being made...that somehow the gl2 is a defective camera and why isn't Canon doing anything to fix it...I think this is heading down the wrong path.

Barry
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Old May 24th, 2003, 01:44 PM   #39
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Barry,
Thanks for putting the issue in proper perspective.
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Old May 25th, 2003, 07:02 PM   #40
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Barry, very well said!

Too many times people forget that these cameras achieve a level of performance that was attainable in the past only with cameras costing thousands of dollars more.

- don
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Old May 25th, 2003, 08:01 PM   #41
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Since terms are being discussed, I would like to offer two explanations of commonly confused terms, Vignetting and Light Fall Off. At first glance these might seem to be the same. But they have different causes and behave differently when the aperture is stopped down (use a numerically larger F number).

Vignetting is caused by an external source, such as hoods, stacked filters, or wide angle adapters. The effect is similar (dark corners) except the dark corners become sharper (more in focus) as the lens is stopped down.

Light Fall Off is caused by internal design of the lens. It is present in all lenses, but is usually not noticeable if the difference from the center to the corner is less than 1/3 F stop. Light Fall Off is most noticeable at maximum aperture and almost always is decreased by stopping down the lens. It is more common at the wide angle position of the zoom, but can occur at any position. The use of aspherical lens elements helps reduce light fall off.
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Old May 27th, 2003, 07:07 PM   #42
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I just got my GL2 today. It has this keyhole problem.. quite noticeable. It sucks especially for me because I will be doing a lot of greenscreen work. I guess I'll have to keep on experimenting to find ways around it. It seems as if the only way I can get rid of the effect is if I go outside and film. heh. There must be some way I can light the screen to reduce this effect...

Here's what I'm getting at the moment... http://www.scifi-pics.com/images/gl2error2.jpg
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Old May 27th, 2003, 10:02 PM   #43
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What settings produced this? (Shutter, aperture, zoom, etc.) There's alot of grain in that frame, suggesting that it was shot under very low light.

Chroma work will require quite a bit of light meticulously distributed evenly across the background with no reflections back to the talent.
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Old May 28th, 2003, 04:11 PM   #44
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The settings were factory default I think. There wasn't a whole lot of light that was hitting the screen (ok, bed sheet) because I had two 600watt lights directed at white boards which were aimed at the screen (hey, it worked with the canon ZR's, heh) so yes that shot was relatively dark. However, I just did another test with the two lights aimed directly at the screen. The fading was still present, although a little bit less noticeable.
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Old May 28th, 2003, 04:43 PM   #45
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I got my GL2 yesterday and played around. Today, I shot my first video to actually bring into the computer and edit for someone. I'm seeing the keyhole effect, but it looks that it would be off normal televisions. I was shooting for the web, so I planned to crop it anyhow. If this is as bad as it gets, I'll be fine with it.

http://joesacher.com/video/edges.jpg

Settings:
Movie Frame mode
Full Wide on Zoom, with stock lense.
F1.6, 0db Gain
Don't remember shutter, probably near 1/60, as I seem to remember it being just bright enough.

Nice to see that Canon is filling the 720 frame with the GL2, instead of the 706 or so plus black vertical bars that I got out of the GL1 I had used before.
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