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-   -   Canon XL-H1 Dead/Stuck Pixels (https://www.dvinfo.net/forum/canon-xl-h-series-hdv-camcorders/146826-canon-xl-h1-dead-stuck-pixels.html)

Isaac Testerman March 28th, 2009 11:47 AM

Canon XL-H1 Dead/Stuck Pixels
 
I have a couple Canon XL-H1's and I love them but recently I noticed that about half the time I capture my footage in FCP there is a dead pixel. It is in a different place each time and is only in about 20% of my shots.
1. What is causing this?
2. What can I do to fix it?
Thanks!

Nick Hiltgen March 31st, 2009 08:23 PM

were you using a 35mm adapter? sometimes those introduce random hot pixels. I don't know why.

Marty Hudzik April 1st, 2009 07:29 AM

I will sometimes get a hot pixel when using the default zoom lens under just the right conditions (usually dark and I Need to add gain) but I don't think I have ever gotten it with the manual 16x lens for some reason. Is there some automatic feature that could heat up the CCD that the 16x lens doesn't trigger?

Also, it seems odd that your stick pixel would be in a different place each time. Typically the stuck pixel(s) is the same one each time. I know it has been for me.

Mark Job April 1st, 2009 11:16 AM

Quote:

Originally Posted by Marty Hudzik (Post 1039629)
I will sometimes get a hot pixel when using the default zoom lens under just the right conditions (usually dark and I Need to add gain) but I don't think I have ever gotten it with the manual 16x lens for some reason. Is there some automatic feature that could heat up the CCD that the 16x lens doesn't trigger?

Also, it seems odd that your stick pixel would be in a different place each time. Typically the stuck pixel(s) is the same one each time. I know it has been for me.

...OK The fact that your stuck pixel is in a different place each time might be a clue as to where your malfunction lies. (??) Canon started using a technology they developped called "Pixel Shift." I think they began using this technology back with the introduction of the XL1. This system has something to do with a moving prism which allows a certain number of pixels to be stretched across an area, which normally would demand a larger sensor and/or greater pixel count. I got a pixel that showed up only once (Thnak God), and I haven't seen one since. I thought it was related to this system.

Marty Hudzik April 1st, 2009 02:11 PM

I don't think pixel shift has anything to do with a hot/stuck pixel moving around. Pixel shift refers to a technique used to achieve a higher perceived resolution with smaller sensors and I believe it achieves this by shifting the green channel in between the others to add "virtual" resolution...but I am not sure so don't quote me on that!

Regardless, it is a permanent shift and would not contribute to hot pixels moving around.

If I misunderstood your post, forgive me. It just sounded as if the theory was that the pixels are "shifting" positions or something, and I don't believe that is the case here. Just different pixels are getting stuck at different times....

Thanks.

Quote:

Originally Posted by Mark Andrew Job (Post 1040275)
...OK The fact that your stuck pixel is in a different place each time might be a clue as to where your malfunction lies. (??) Canon started using a technology they developped called "Pixel Shift." I think they began using this technology back with the introduction of the XL1. This system has something to do with a moving prism which allows a certain number of pixels to be stretched across an area, which normally would demand a larger sensor and/or greater pixel count. I got a pixel that showed up only once (Thnak God), and I haven't seen one since. I thought it was related to this system.


Mark Job April 1st, 2009 02:35 PM

Quote:

Originally Posted by Marty Hudzik (Post 1040628)
I don't think pixel shift has anything to do with a hot/stuck pixel moving around. Pixel shift refers to a technique used to achieve a higher perceived resolution with smaller sensors and I believe it achieves this by shifting the green channel in between the others to add "virtual" resolution...but I am not sure so don't quote me on that!

Regardless, it is a permanent shift and would not contribute to hot pixels moving around.

If I misunderstood your post, forgive me. It just sounded as if the theory was that the pixels are "shifting" positions or something, and I don't believe that is the case here. Just different pixels are getting stuck at different times....

Thanks.

... :-) No problem. You essentially expressed the same idea as I was trying to explain. It is not the pixels blocks themselves which actually move, but I thought it was a specially designed prism mount Canon had perfected, which could "shift" its position to allow pixels to cover an area which would normally require a larger pixell block (CCD) with more pixels on it. I could be wrong here too.

Harry Bromley-Davenport April 2nd, 2009 09:24 PM

When you are about to shoot a scene and you see on the monitor that you have a dead pixel, it may be worth trying the following:

Open up the aperture to maximum and blow the whole system out to white.

Then close down and re-boot.

I've shot three features on the XLH1 and this sometimes works.

I have also sent it back to Canon and had the dead pixels "mapped out"

Other than that, I have used a pixel fixer piece of software on bad shots which allows you to find the bad pixel and kill it in your dailies.

Hope this helps -- believe me, it's fixable. It happens all the time and it's only really visible, as you know, when there is a dark background.

best

Harry

Isaac Testerman April 2nd, 2009 09:34 PM

Thanks Harry, I'll remember to do that. It is in about 10% of my shots and when i turn the camera off it does fix the problem. However the pixel that is dead is to small to see in my view finder... which leads to another problem...why can't they make viewfinders that are color and high def. Well I know why but they need to find a fix for that.


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