HVX200 and Green screen

[Graeme Nattress]

You should be able to do good blue or green screen with it, but really, for best results, it’s always best to take a direct uncompressed HD SDI feed off the camera (and the HVX200 doesn’t have this) and use that. Compression hurts the quality of the key as much as chroma sampling does.

Graeme

– http://www.nattress.com – Film Effects for FCP

[Noah Kadner]

That and very careful lighting are what will make an easy key.

Noah

[Jeremy Garchow]

For what it’s worth, I have pulled a couple of keys off of varicam tape (not uncompressed) and have been very pleased with the results. I was even able to use Final Cut’s keyer on one of the jobs ( we had to move very fast and after effects rendering would have taken too long). Granted, this was not for broadcast, but for a large corporate presentation projected on a 40 foot widescreen. Closest thing to the movies as I’ll probably ever get. The results were very favorable. i was able to achieve an even better and smoother key in after effects using keylight, the keying plug in that is shipped with after effects. This process took a little longer than using FCPs keyer. While Graeme is correct, an uncompressed signal coming straight out of the cam is ‘better’, with the right amount of patience you should be able to pull a nice chromakey. Just so you know, we shot on green. I imagine the results of the HVX200 should be the same since it’s recording the same codec as the varicam. make sure you bring a waveform with you onsite to make sure your screen is lit evenly and properly (not too bright or dim). This will save you a lot of time in post.

Cheers

Jeremy

[Graeme Nattress]

If you have good lighting you can pull a good key off VHS! Yes – that’s the key, more than any video format or special camera – a good wrinkle free screen and good lighting. An hour spent getting the lighting right saves 10 in post 🙂

Graeme

– http://www.nattress.com – Film Effects for FCP

[Noah Kadner]

Also another trick I use is zebra. Crank the f-stop open as you are lighting the screen. You’ll see zebra whereever something is unevenly bright on the screen. Keep working on the light until there’s no hot spots. Then try to get as little spill as possible onto the actors by lighting them seperately.

Noah

[Jeremiah Black]

Well, I’ve never green screened for as big an area as Jeremy, but I’ve done quite a bit of greenscreening on the DVX-100a. It came out pretty good, but it was a nightmare to do (4:1:1 color, 5 to 1 compression). Took forever in post.

I can’t wait to try it on the HVX-200!

No matter what the foramt, I’ve found that Ulimatte AdvantEdge in After Effects is the best keyer.

I’ve done green screen at 24p, 24a, and 60i; and I found that 24pA came out the best, and 24p with a 3:2 pulldown came out the worst. Anyone else care to share there experiences with various frame rates?

– jeremiah black, NYC

[Deleted User]

[Noah Kadner] “Also another trick I use is zebra. Crank the f-stop open as you are lighting the screen. You’ll see zebra whereever something is unevenly bright on the screen. Keep working on the light until there’s no hot spots. Then try to get as little spill as possible onto the actors by lighting them seperately.”

I agree. An effective “zebra/chromakey” technique I’ve used (and I believe I first saw it mentioned on the COW in a post by Leo T.?) is to start with the cam’s zebras set to around 70 IRE. As Noah says, light the green or blue screen so the zebra stripes become completely even across the entire frame with hot spots over 70% & no dark areas under 70%. When this is accomplished, close the cam’s iris by one (1) full f-stop. The green/blue screen is now exposed one f-stop darker than 70 IRE, a level recommended by many experienced shooters.

Then adjust the lighting for your foreground subject (actors, products, etc.) without changing the cam’s f-stop. For example, if the subject is a person, a zebra setting of around 70 IRE is often appropriate for caucasian skin. Adjust the subject lighting so the subject is properly exposed, rather than adjusting the cam’s iris.

Since you need to keep adequate physical separation between the subject and the blue/green screen to prevent the screen’s color from reflecting back onto the subject (which makes clean keying much more difficult), you should be able to light the subject without its light adversely affecting the blue/green screen lighting & vice versa.

I’ve used the above zebra/chromakey technique with great results using the DV codec (thanks, Leo!) There’s lots more chromakey lighting technique discussed in the COW’s Pro Lighting forum & archive.

– Peter

Just a friendly reminder to all: Please consider filling-in your COW user profile information so we have a better idea who you are, where you’re from, and so forth. It’s the friendly thing to do. Thanks!

[Noah Kadner]

Throwing out a little plug- I’ve had excellent results with DVX100 footage using Graeme’s G-Nicer plugin to upsample the 4:1:1 chroma info. Results are amazing with the FCP built in keyer.

Noah

[Barry Green]

Be sure to look at this link, for an example of how superior 4:2:2 DVCPRO50 is, as compared to 4:1:1 or 4:2:0 DV:

https://www.eleventy.org/dv-en/

—————–
Get the most from your DVX camera. The DVX Book and DVX DVD are now available at https://www.dvxuser.com/articles/dvxbook/ and at Amazon (https://tinyurl.com/54u4a)

[Deleted User]

[Peter DeCrescenzo] “… light the green or blue screen so the zebra stripes become completely even across the entire frame with hot spots over 70% & no dark areas under 70%. …”

Oops, typos: This phrase should read:

“… light the green or blue screen so the zebra stripes become completely even across the entire frame with _no_ hot spots over 70 _IRE_ & no dark areas under 70 _IRE_. …”

All the best,

– Peter

Just a friendly reminder to all: Please consider filling-in your COW user profile information so we have a better idea who you are, where you’re from, and so forth. It’s the friendly thing to do. Thanks!