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blotchy, noisy green screen shot with Sony PXWZ100
Video camera novice here. Getting started with a dance-based video project by taping dancer in front of a green screen. Monday, to set up the shots, I went to the dance studio, which is a gym with aweful 30-foot high flourescent lights, half of which are burned out and shot with all settings on auto with my small Sony AVCHD camera. Got the footage, looked good, keyed out the green screen with Keylight 1.2, fantastic. But yesterday, to take demos for the real shoot, I brought in my bright, but cheap interview-style video lights and shot in 1080p XAVC (4:2:2) on my new Sony PXWZ100 camera (using all auto settings).
Got the footage into After Effects CC and noticed when keying everything was blotchy with moving static/noise/grain–even when I manipulated to get a solid key, the subject, particularly the hair looked like a bad TV plugin. Even when not keyed, if I scaled up, I saw the blotchiness on the whole shot, both the green screen and my subject. , so I don’t think this is a Keylight issue (I know it doesn’t light very bright green). Transcoded footage to uncompressed, same results. Tried despoil and noise reduction without much success for a convincing final product.
Thoughts on what I should look at or change? I suppose I can try it again without video lights. Or learn how to manually set the white balance if that is the heart of the issue.
Any thoughts would be very welcomed.
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2 Replies
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I also have a lot of noise with my PXW-Z100. If you look at the demo video from Sony, You will see the same noise. With the use of NEATVIDEO the noise will be acceptable..
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Actually, i do not understand fully how to calibrate the z100 because with vegas12, the shots are not displayed in the colorspace of my calibrate screen sRGB. I by vegas13 5 days ago and now the compatibility with my screen is right. The first benefit is that the noise is less visible than with vegas12. The profile values in Neat video confirm my visual impressions. But it seems that i need to recalibrate the black of my pxw-z100 because i do not have superblack. The minimum rgb value is 17 and with std6, the max is 253. I can correct this problem if i change the bottom value of the gamma curve but it is not interesting to have to do this for all my shoots. I do not find information about jpeg2000 and xavc concerning the rgb value 16 and 235 and how vegas13 converts them in rvb 8bits and show them in the vectorscope. So, I need to do more tests with my sekonic chart with 25 patchs on 4IL to discovering all by myself. When the 18% grey will be 118RGB, the 0%(or-9%) = 0RGB and the 100%(or 109%) = 255RGB then the setup of my z100 will be correct and the shoot displayed without further corrections when i use my lightmeter and do the white balance on PVDF chart(téflon).
All remarks are welcome on flickr.com in a group called Sony pxw-z100 4k
There, i present all my knowledge and informations that i had found about the pxw-z100. Dynamic, Matrix, gamma, zebra, knee, noise ,sharpening, difraction….. in french but english is possible.On xdcam-user.com, Alistair Chapman give some recommandations about green screen shot.
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