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Am I the only one who see's these lines???


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#1 James Briggs

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Posted 15 May 2007 - 09:14 AM

I have been using my XL2 now for a long time on many different projects and it is all going great! I can get everything I want considering low budgets so its a dream.

But my one query which I have found is that around the edges of stuff at times is like a jagged effect. It's always around sharp lines or edges. I notice if I turn down the detail it is greatly minimised but even so is still faintly there. I have noticed also this year spotting it on the odd TV program. Now I'm wondering if it's just me going mad! But I haven't ever seen these lines appear from any other camera I have used or worked with unlike the XL2.

Does anyone else know or have a clue what I'm talking about? And maybe can explain why this happens.

I have tried changing the vertical detail but this seems to make no difference at all. But I think it does greatly change depending on the monitor it is playing back on. It appears even through the actual viewfinder and sometimes double as bad. It's really bugging me. Strange...

(I did remember seeing in a review once a negative comment about vertical line issues)

Thanks!
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#2 Patrick Neary

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Posted 15 May 2007 - 09:21 AM

Hi-

it's an artifact of scan lines and low resolution.

welcome to standard-def TV!
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#3 James Briggs

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Posted 15 May 2007 - 10:59 AM

So will it disappear on high def TV's?

Other camera's don't seem to have the problem but then I know the amount of lines used is extra in the XL2 than most so that would explain it. Is there anything I can do in editing to get rid of them though or something I can run it through. Or am I just stuck with it and anything filmed with XL2 can not have this probelm fixed. Other projects people have mentioned which were released apparently done on the XL's don't show this. Or maybe that's because they use XL1's? It's a very annoying flaw. Being a perfectionist and so into all the detail I feel it really detracts and certainly destroys any illusion if it being film or even close to it.
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#4 Joseph Winchester

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Posted 15 May 2007 - 12:12 PM

Can you post a photo of this effect?

I have used both the XL2 and XL1 for years with no issues like what you describe.

Is this problem only happening on your computer monitors? If so, that's normal. It has to do with the pixel aspect of computers (square) and tvs (not square pixels). But it shouldn't happen on a standard television. Try viewing it on an NTSC tv. That's the only thing I can think of.

Edited by Joseph Winchester, 15 May 2007 - 12:13 PM.

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#5 Patrick Neary

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Posted 15 May 2007 - 12:33 PM

I'm guessing this is what you're talking about (random google hit):

http://www.donferrar...m#stairstepping
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#6 James Briggs

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Posted 15 May 2007 - 04:57 PM

Thanks for the response guys!

Yes Patrick that's it exactly. Finally now I know how to describe it properly. This is exactly the problem I am having.

Hi Joseph. No annoyingly this is appearing on TV not just my computer. So it's a real pain. This is another reason I was so confused because many people seem to have no problems at all! Or have noticed nothing.

I am using the pal version not the NTSC version as I come from the UK. Does anyone know if this is infact only a problem with the pal XL2 cam's then? This effect doesn't seem to happen for many XL users and I couldn't see any other thread on here with anyone mentioning it at all.
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#7 Michael Collier

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Posted 15 May 2007 - 09:04 PM

Its an artifact of the cosine compression in DV. Any mini-DV camera will have this. Some are less apparent becuase the chip has less resolution, or the glass is softer, etc, but any DV camera is capable of generating this artifact. Its not truely a result of having too few scan lines or interlacing or any of that, its just that the codec is trying to reduce the amount of information in picture. With any cosine compression the first noticable effects will be in high contrast, high frequency detail. No real way around that. reducing the detail softens the image and reduces both contrast and detail freqency, but it does nothing to mitigate the way the compression attacks a scene like that. You could try running the analog out into a (non-firewire) analog capture card, or get an adromodized DVX-100, or get a beta-sp/beta-sx/digi-beta camera, though all those options are costly and have logistics issues.
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#8 Patrick Neary

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Posted 16 May 2007 - 10:08 AM

Hi-

that may be so, but you can see stair-stepping in other NTSC/PAL-originated stuff, including digi-beta (the feature "The Fast Runner" comes to mind) despite the better anti-aliasing those cameras have. It's not hard to find in any video-originated material if you really start to look for it. It's very pronounced on digital-to-film projects. I think it's like dust specks on film, you kind of tune it out normally, but if you start to look for it, it will drive you nuts!
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#9 James Briggs

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Posted 18 May 2007 - 08:04 AM

Thanks Patrick and Michael for all your feedback!

Maybe I am just being too picky. It's just for some reason it seems to look more obvious to me with my XL2 than other camera's. At least now I know what it is.

I don't think I would want to go with another camera as the XL2 otherwise offers all the picture control and best results for general camera work I want to do.

Does anyone know if the problem is reduced with HDV for when I can afford to upgrade?
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#10 Michael Nash

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Posted 18 May 2007 - 04:56 PM

Does anyone know if the problem is reduced with HDV for when I can afford to upgrade?


It's called aliasing, and it's inherent to all standard def cameras. Detail enhancement and DV compression can make it look worse, but it's generated by the number of scan lines in the camera.

HD cameras have more lines of resolution, so aliasing appears finer compared to standard def.
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#11 Mike Andrade

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Posted 25 May 2007 - 03:08 AM

James,

I dealt with the same aliasing issues you mention when I first got my XL2. I had really nice footage that was ruined by a power line or brick wall in the shot. The only workaround I found is to stay away from tight patterns of any sort such as roofs, brick walls, and power lines as much as possible. It seems to be way more prevalent in wides as well. Talent wearing a striped shirt can be really bad also.

Edited by Mike Andrade, 25 May 2007 - 03:09 AM.

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