HPX500 not good for green screen?

B

Bandido

Member
A was reading an article by Art Adams at the ProVideoCoalition web site. The article name is "I decide - The Anatomy of a No-Budget HD Spot". In the article he said that they couldn't pull a clean chroma key because "the HPX500 does not have a native HD sensor, it is (720x960)", so the up-resizing created the jaggy edges around the subject. At the end he fixed the problem in post. He explains the process in detail and it seems like a lot of unnecessary work to me; too much hassle. Anyone has a different experience with this camera?. If Art Adams is right, then, the HVX200(a) and HPX170 should show the same problem with chroma keys. I always thought that all these cameras were good for this type of work due to the DVCPRO HD codec and it's 4:2:2 color space. The question is, Which camera is more suitable for this kind of job, the HPX500/HPX170/HVX200(a) with their 720x960 sensor and 4:2:2 color space or the Sony EX1/EX3 with their full raster (1920x1080) sensor but 4:2:0 color space?:huh:
 
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Bandido said:
A was reading an article by Art Adams at the ProVideoCoalition web site. The article name is "I decide - The Anatomy of a No-Budget HD Spot". In the article he said that they couldn't pull out a clean chroma key because "the HPX500 does not have a native HD sensor, it is (720x960)", so the uprezising created the jaggy edges around the subject. At the end he fixed the problem in post.:
Click to expand...

If he couldn't pull a good green screen from the HPX500, he has not talent for green screen.

That is all there is too it. I have a green screen from an HVX200 that has singular blond hairs blowing in the breeze and it is beautiful. No problem.

Sometimes these guys just get so wrapped up in the technical numbers that the real challenge of pulling a good green screen. Keep in mind that 4:2:2 is a RATIO of luminance to color. 4:2:0 references the fact that there is color on every other line. Number of luminance doesn't count if the ratio is not there.


Best,
Jan
 
not to mention the long gop on the sony doesn't help. i have shot tons and tons and tons of greenscreen on the hvx200 and hpx500. i key most of it myself and it's awesome. perfect keys every time.
 
I pull excellent HPX green screen keys every week, no problem.

With the 4:2:2 colorspace it is easy cheesy.

You be the judge:

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We shoot our DVDs greenscreen. It's incredibly easy. Jim Arthurs called the 4:2:2 on the HVX a "breakthrough" in keying simplicity.
 
I did a quick GS test on the hpx170 two nights ago and the results were great. not sure why Art had a bad experience.
 
Hi Bandido,

I think that's a load of, well, hooey.

As one who's written about (Google "Making A Green Screen With Local Materials") 100,000's of hits and growing and done a lot green screen work myself, the HVX200 has been a pleasure to work with in getting great keys.

Anyone would rather work in 4:2:2 color space rather than 4:2:0 any day for keying content.

This hooey about the sensor is just krappe.
 
Here's one for ya:

I shoot green screen every friday with an HPX 500, not against an actual green screen but against a rear screen projection system (showing a green solid image) that I wouldnt exactly call evenly lit by any means. It has a giant hot spot in the center and is darker around the corners.

That, and it's shot in DVCPro 50.

Pull a clean key every time (Avid SpectraMatte). So no, I wouldn't call the HPX too limited for green screen use.

FYI I used an HVX 200 under the same conditions but against a blue screen and shot in DVCPro HD to do a screen test about a year ago, and it worked just fine as well.
 
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