EX1 + ReflecMedia ChromaFlex Experience?

puredrifting

puredrifting

Major Contributor
Hi all:

I am about to embark on shooting several projects with the EX1. Because of travel issues and having to shoot interviews in people's tiny, ugly spaces, I am interested in trying to shoot greenscreen with the ChromaFlex system.

Has anyone successfully used the ChromaFlex system with the EX1 yet? Anyone have any results they can share? I am going to shoot some tests to see what kind of key a super high resolution camera with poor color space can pull and will post my results.

Anyone have any detail menu recipes that have worked well for greenscreen with the EX1? I have seen some other green screen here with the EX1 that looked okay but was shot with traditional green screen, not the ChromaFlex system.

Thanks,

Dan
 
It looks like the only advantage RelectMedia has is eliminating the need to set up an evenly lit green screen. Otherwise the keying process is the same as shooting conventional green screen.

It would help in spaces that are tighter than usual. However it may or may not work well with certain types of hair or under certain situations. If the Chromatte material isn't hit by the coaxial light source in a way that allows it to bounce back to the camera, the all-important green screen won't appear where it should -- and that could affect the quality of the edges.

As for keying software, I highly recommend Primatte. There's a lot of controls in it that helps pull some excellent keys.
 
It looks like the only advantage RelectMedia has is eliminating the need to set up an evenly lit green screen. Otherwise the keying process is the same as shooting conventional green screen.
Click to expand...

Yep, currently the highest end camera I've tried it with is the DVCPRO HD output from an HPX500. What I'd really like to compare is the final output of the EX1 vs an HPX. Sure we could get technical with the 4:2:2 vs 4:2:0 color space and 1920x1080 blah blah. But, what really matters is the final product. Just how real does the key look if shot with both cameras. Hmm.. I guess another way to look at is... you can have 2 EX1's or just 1 HPX500. Or hmmm 1 EX1 and a heck of a lot of sushi :) I like sushi!
 
Phil Bloom has a video evaluation on this approach to green screen. Look it up!
 
EX Chroma Key

EX Chroma Key

Hello,

A good friend of mine uses EX1 and a Reflectmedia setup. He seems to be very satisfied with his findings. You´ll find a video example to watch here:

http://www.vimeo.com/1054795

I´ve been using a portable Reflectmedia rig for a couple of years, both with the Canon XL2 (DV) and the Panasonic HVX-200 (HD) in a lot of different scenarios. I´m generally very pleased with the results. I can recommend using a solution like this, even if it has some "limitations" (ex. items where the green/blue LED-ring can be seen should be avoided). For interviews and even full body shots it´s very easy to get quality results. Please spend some time familiarize yourself with the set up, before your project starts.

After seeing examples of chroma keying using the Sony EX1 I´m quite impressed with the quality. I haven´t experienced pulling a key from this type of footage myself, so I´m just sharing my first impression of "keying in 4:2:0 HD".

The best of luck with your project.

Best wishes,
Terje Rian
 
I only used the ChromaFlex setup when still filming with the XL2 a lot and wasn´t that pleased with the results.
I guess it was due to too little testing and tweaking.
What I still don´t know is how to set the right intensity for the LED ringlight, there was always to much green on the talent.
But the edges usually where pretty clean for a DV key, so HDV should be fine too...
 
trian said:
Hello,

A good friend of mine uses EX1 and a Reflectmedia setup. He seems to be very satisfied with his findings. You´ll find a video example to watch here:

http://www.vimeo.com/1054795
Click to expand...

That composite looks great! That's the kind of stuff I really wanted to see.

While googling I found an interesting post from a Sony rep regarding keying and the EX1

Juan Martinez directly quoted below:



Actually, the Ex1 outputs honest to goodness 10-bit 4:2:2 at all
resolutions via its built-in HDSDI/ SDI interface.

Now, a word about "color space". In the old SD days, 4:4:4, 4:2:2 and
4:2:0 had absolute meaning and direct correlation to the picture
quality (luminance and color resolution). In the case of HD, 4:4:4,
4:2:2 and 4:2:0 are relative. Thus, these ratios have no "real"
meaning anymore. Therefore, it would be possible for an HD format
with small luminance and color spatial resolution to claim 4:2:2...
so, the only way to compare is to count the actual captured pixel
resolution. Once, you know the exact number of luminance pixels
stored, you can apply the ratio to compare apples to apples (for a
given aspect ratio).

For compositing, all that is necessary is for color sampling to be
tight enough for the keyer to effectively detect the edges. You will
find that Ex captures 960 color pixels in the horizontal direction
capturing a higher color resolution than some HD formats. The color
sampling is also halved in the vertical to 540, which is still
suitable for good keying. Lastly, at the core of modern compositing
engines are sophisticated keying algorithms that even look at
luminance transitions to more accurately detect the edges. Please try
keying with Ex 4:2:0. I believe you will be surprised how good keys
you will be able to achieve.

Sorry for the long winded reply. I hope it helps.

Juan Martinez
Senior Manger Technology
Sony Electronics
Click to expand...
 
I wonder what Barry would have to say about that. I guess is makes some sense because of how crazy efficent some of these codecs are these days.
 
I do keys routinely with the EX1 and get outsanding results.

The keyed shots of our host against outdoor backgrounds look natural. No bad edges, and her hair is kept intact.

The usual comment, even from an experienced DP, is "that was green screen?"

I'm using a conventional green screen from EEFX.com and Lowel lights. But the "star" of the process is Primatte. This keyer apparently depends upon a 3D model of color space, and is able to define what is and isn't part of the matte.

Among the really powerful features is "Lightwrap", where it takes pixel values from the background plate and can softly blend the foreground element's edges. Bright areas behind the talent can be made to flare into the foreground as it would in real life. And light edges of the foreground are also blended into the dark background areas.

It also handles green spill very well, with a variety of fine-tune controls. If you're serious about doing quality green screen work, I can't recommend this software enough.
 
trian said:
Hello,

A good friend of mine uses EX1 and a Reflectmedia setup. He seems to be very satisfied with his findings. You´ll find a video example to watch here:

http://www.vimeo.com/1054795

I´ve been using a portable Reflectmedia rig for a couple of years, both with the Canon XL2 (DV) and the Panasonic HVX-200 (HD) in a lot of different scenarios. I´m generally very pleased with the results. I can recommend using a solution like this, even if it has some "limitations" (ex. items where the green/blue LED-ring can be seen should be avoided). For interviews and even full body shots it´s very easy to get quality results. Please spend some time familiarize yourself with the set up, before your project starts.

After seeing examples of chroma keying using the Sony EX1 I´m quite impressed with the quality. I haven´t experienced pulling a key from this type of footage myself, so I´m just sharing my first impression of "keying in 4:2:0 HD".

The best of luck with your project.

Best wishes,
Terje Rian
Click to expand...

Man, that looks great! I have yet to get that clean of a key. I don't use after effects or keylight.

Any advice for the EX1/Reflect media using Apple Motion?
Also, could it be how I shoot it? What kind of separation are you giving your subject and the background?

Thanks.
 
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