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class="style14">CineAlta vs Varicam for Greenscreen

>Published : 30th Oct. 2006

>Hey everyone,

>I'm prepping for a Music Promo that is about 80% greenscreen, with CG backgrounds composited into them. Production wants to shoot HD, and my usual supplier only carries the F900. The director wants to look at a Varicam, so that he can edit at home on Final Cut HD.

>There is the beginning of a discussion as to which system is better for Greenscreen on the Cinematography.com site, but no conclusions, so I'm asking if anyone here has experience of shooting greenscreen with the two systems, and which you would recommend.

>Thanks

>Stuart Brereton
DP, Bristol, UK
http://stuartbrereton.com/


>Stuart Brereton wrote :

class="style15">>>I'm asking if anyone here has experience of shooting greenscreen >>with the two systems, and which you would recommend.

>In my experience the Sony is the better tool, compression artifacting from dumbing HD down to the 40Mbs Panasonic codec renders keyers fairly useless, as there is no clean edge to key, only jaggy blocks of ugliness

>If the show has 80% greenscreen should not the Vfx sup and or Vfx house have a say in this? Perhaps run tests if they do not have direct experience... assume nothing!

>As a side note the other option for highly compressed HD, Avid's Hdnx codec isn't much better at it's lowest quality settings, and no one would willingly use that codec to extract matts either if they had done it once.

>Best options I have been involved with is the Viper feeding HDSR good luck, test test test, and then test once more.

>Dermot Shane
Vfx, post, and sometimes camera pointer
Vancouver, B.C.


>Dermot Shane wrote :

class="style15">>>In my experience the Sony is the better tool, compression artifacting >>from dumbing HD down to the 40Mbs Panasonic codec renders >>keyers fairly useless, as there is no clean edge to key, only jaggy >>blocks of ugliness

>I'm not sure where you got your number but this type of answer distracts from what I consider the real issues in comparing the options.

>I often get asked whether the Varicam or HDCam is better for compositing. My answer is always "What are you recording on?" because if you want the best quality HD for compositing, you had better start by not recording in either camera.

>When you start trying to pull a matte, you are looking for colour resolution adequate to separate blue from green, one way or the other. The HDCam and Varicam both record 480 samples of colour information across an HD line. For the HDCam, this represents fewer samples with respect to luma information but it is low in both formats. If you record on an external hard drive, a D5 recorder or an SR deck, you can get up to 960 for HDCam and 640 for Varicam. That is 50% to 100% more colour information that you can get with either format in-camera, not to mention the increase in luma resolution in both formats.

>However, neither of these implies editing at home on Final Cut in compressed HD, presumably what the director is thinking about. On the other hand, if this Music Promo will never see a big screen, either may be adequate for his needs. It also sounds from his evaluation so far, that he might not know the difference.

>I teach Varicam workshops, but I do not attempt to mislead my clients into believing that, because you can record in camera and dump through Firewire into a laptop, then edit in your airplane seat, that this is the way to go for projects requiring serious processing like compositing. You have to look at the end products and the entire workflow to figure out which tool is best for your job.

>If you decide that you need 1920-pixel resolution for compositing or big screen use, then you had better consider external recording, because just going to HDCam won't give you that type of quality by itself. And, of course, there are other camera options, but that's another discussion, which is rehashed here regularly.

>cheers,

>Charles R. Caillouet, Jr.
Vision Unlimited/LA (the other LA)
HD production technical support since 1987
HDExpo Workshops Staff
...searching for the right tools for the job...


>Have done greenscreen with both and both systems work just fine. Ask yourself these questions :

>1/. Am I after resolution or
2/. Am I after colour information and high speed capabilities

>If you answered 1 you want to shoot on the Sony
If you answered 2 chose the Panasonic

>Besides economics, not much more to it imho

>Florian Stadler, D.P., L.A.
www.florianstadler.com


>In practice both the F900 or the 27f should work well. Our preference is for the AJ 27f due to the ability to use Cinegamma curves and also its variable frame rate capability, though variable frame rate may not be a requirement for you.

>If you are posting in FCP, which I think is a great way to go, capture at 1080/25P (25P I assume if it is a UK shoot) 10bit uncompressed from the 1700 deck which will upconvert for you from the 720 native to 1080 with out problem and go from there. Offline in DV. In recent months I haven’t used native 720/25/60 in DV100 in an FCP timeline, there was an audio issue with it at this frame rate which was problematic. (Any one know if this is cured yet ?)

>If your in Bristol UK, then Id be pleased to show you some systems working in HD this way in FCP/Final Touch etc with various keying software if this would help.

>Dave Blackham
Granada Television
Bristol UK


>Dave Blackham wrote :

class="style15">>>there was an audio issue with it at this frame rate which was >>problematic. (Any one know if this is cured yet ?)

>I'm still wondering why this isn’t argumented/discussed here more - I can't understand why this isn’t implemented in FCP after two generations of software development.

>What the ____ is so difficult to make a straight 720/25P workflow available?

>If anyone could explain that to me (off list if you want), I stop to ask those question...

>+++ Florian Rettich +++
+++ D.I.T. (US) / D.F.T. (UK) +++
+++ Munich, Germany +++


>Dave Blackham wrote :

class="style15">>>there was an audio issue with it at this frame rate which was >>problematic. (Any one know if this is cured yet ?)

FYI... the camera-mounted DVC-822 (new improved version) takes care of the audio issue and can provide an HD and SD output based on the Varicam flag i.e. 720p25 for HDSDI output and 625/PAL for SDI/Composite/DV outputs.


( http://www.miranda.com/product.php?i=226&l=1 )

>Gilbert Besnard
Director, Product Development
Miranda Technologies Inc.


class="style15">>>there was an audio issue with it at this frame rate which was >>problematic.(Any one know if this is cured yet ?)

>I'm still wondering why this isn’t argumented/discussed here more - I can't understand why this isn’t implemented in FCP after two generations of software development.

>I have no idea what this Audio hasn’t been sorted yet. In my view it hinders the sales of both products so should have been in everyone’s commercial interests to resolved by now. It is only an issue with 720/25 over 60 compressed DV100 replay so far as I am aware. Be that as it may, FCP 5 just arrived in our facility so ill check it out in that and see if it is fixed.

>Thanks for the Miranda link too.

>Dave Blackham
Granada Bristol
UK