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Viper Filmstream and Green screen


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#1 ViperMan

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Posted 19 July 2005 - 09:07 AM

Hellow everyone!

Does anyone have experience on filming a Green Screen in Viper's Filmstream mode?
We're going to run some tests these days!
We think that we might get in trouble when pulling a matte, because the Filmstream mode produces an overall green image.
So our keying software (Quantel eQ) may think our foreground actors are too green also and include them in the matte.

Would it be a good solution to film with a megenta filter in front of the lens, to correct for the green in the image. (Maybe also affecting the backgroud green a little...?) Any other suggestions are very welcome!

Gretings,

Dennis Verheijen
Pentamagik
The Netherlands
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#2 Stephen Williams

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Posted 19 July 2005 - 10:24 AM

Hellow everyone!

Does anyone have experience on filming a Green Screen in Viper's Filmstream mode?
We're going to run some tests these days!
We think that we might get in trouble when pulling a matte, because the Filmstream mode produces an overall green image.
So our keying software (Quantel eQ) may think our foreground actors are too green also and include them in the matte.

Would it be a good solution to film with a megenta filter in front of the lens, to correct for the green in the image. (Maybe also affecting the backgroud green a little...?) Any other suggestions are very welcome!

Gretings,

Dennis Verheijen
Pentamagik
The Netherlands

<{POST_SNAPBACK}>



Hi,

To get the best out of Filmstream you should oplically filter the image using a MFX Digital designed filter, for your white balance.

For more information www.digitalpraxis.net


Stephen
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#3 Rob van Gelder

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Posted 20 July 2005 - 10:46 PM

Dennis, are you keying the unprocessed Filmstream data?
I thought, that after you have adjusted the image for the right look, color balance, detail, etc, THEN you apply the key?


or is it for live-keying?
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#4 Kai.w

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Posted 21 July 2005 - 08:03 AM

Hellow everyone!

Does anyone have experience on filming a Green Screen in Viper's Filmstream mode?
We're going to run some tests these days!
We think that we might get in trouble when pulling a matte, because the Filmstream mode produces an overall green image.
So our keying software (Quantel eQ) may think our foreground actors are too green also and include them in the matte.

<{POST_SNAPBACK}>


I had to key some viperfootage which wa shot in filmstream mode. It was converted to 12 bit in Flame with a lut that got rid of most of the green cast of the image (leaving the greenscreen quite right). I found the images to key very well.
If you're interested I could send you a frame...

send me a pm with your mail if you're interested.

-k
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#5 ViperMan

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Posted 21 July 2005 - 08:38 AM

Dennis, are you keying the unprocessed Filmstream data?
I thought, that after you have adjusted the image for the right look, color balance, detail, etc, THEN you apply the key?
or is it for live-keying?

<{POST_SNAPBACK}>



Yes, we will be keying the unprocesseds Filmstream data.
Since our green screen hasn't been finished yet, we don't have any material for testing yet. But I would think that color correcting the image with green screen would also affect the color of the screen. So keying could be looking less good?
But now you mention it, it is worth trying.
As we'll do some testing I drop my experiences in here!

Feel free to add any advices!

Dennis Verheijen.
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#6 Gavin Greenwalt

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Posted 19 October 2006 - 01:57 PM

Yes, we will be keying the unprocesseds Filmstream data.
Since our green screen hasn't been finished yet, we don't have any material for testing yet. But I would think that color correcting the image with green screen would also affect the color of the screen. So keying could be looking less good?
But now you mention it, it is worth trying.
As we'll do some testing I drop my experiences in here!

Feel free to add any advices!

Dennis Verheijen.


If you were shooting in 8 bit linear that would be a problem. The great thing about shooting log or half float is that there is more data there than "meets the eye" on a reference monitor. Even if you reduced the green cast by 50% you still aren't going to get color artifacts because of the color precision. Think of the color of your green screen with the Filmstream green cast as "super green", yes it will get less green, but only to normal acceptable levels. If this wasn't the case all viper films would be completely lacking in rich greens, which would be unacceptable.

- Gavin
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Visual Products

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