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Jiban Huidrom

cheapest camera for perfect green screen work

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newbie with ML RAW and big file sizes might be a very steep learning curve .......

so option 2 ;

 

I would recomend a Panasonic G6 - superb camera in my opinion the best non raw DSLR out there right now

its small , light and cheap and easy to use and takes a superb very very sharp cinematic image with 'normal' managable size files

Ive had no issues on green screen with it

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newbie with ML RAW and big file sizes might be a very steep learning curve .......
so option 2 ;
 
I would recomend a Panasonic G6 - superb camera in my opinion the best non raw DSLR out there right now
its small , light and cheap and easy to use and takes a superb very very sharp cinematic image with 'normal' managable size files
Ive had no issues on green screen with it

No HDMI out and limited to 28Mbit 4.2.0 How is that good for green screen work?

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No HDMI out and limited to 28Mbit 4.2.0 How is that good for green screen work?

 

Well, HDMI out doesn't mean anything for pulling a key- but 4:2:0 does.

That being said, I've pulled some really sharp keys with compressed 4:2:0 - much better than I though I would be able to, but I needed to run the footage first through 5DtoRGB to do a better color space conversion first, otherwise you get some jagged lines around the edges. 

A 4:2:2 or higher would be better, and a camera that shoots RAW like the 50D with a hack or Black Magic Pocket cam would be best!

 

Yes, the files are large and unweildly, but to get a good key with a Panasonic AVCHD 4:2:0 camera would also have a bit of a convoluted workflow- so it balances out somewhere. 

 

Meanwhile, I'm noticing a common trend with Andy's posts. He really loves his G6.  ;)

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Meanwhile, I'm noticing a common trend with Andy's posts. He really loves his G6.  ;)

 

Its not my G6 its Panasonics G6 ....they have made a great camera

2 things have happened in the past 4 months Magic Lantern RAW on Canon cameras and Blackmagic pocket camera

both are great for certain jobs but both have caused people to loose sight of how good the G6 really is straight out the box

 

I was an early adopter and I seem to be the only person using this camera on here alot , Its now my main camera over the GH2s

the image is better than my Driftwood 150mb/s hacked GH2 ...straight out the box for me that is an amazing thing as the file sizes are now smaller and the image is better

I have no idea how Panasonic have done this but they have and it works

So yes I do highly recomend the G6

I can record 2.5 hrs on a cheap 32gb card and I stll get stunning images off the G6

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Its not my G6 its Panasonics G6 ....they have made a great camera

2 things have happened in the past 4 months Magic Lantern RAW on Canon cameras and Blackmagic pocket camera

both are great for certain jobs but both have caused people to loose sight of how good the G6 really is straight out the box

 

I was an early adopter and I seem to be the only person using this camera on here alot , Its now my main camera over the GH2s

the image is better than my Driftwood 150mb/s hacked GH2 ...straight out the box for me that is an amazing thing as the file sizes are now smaller and the image is better

I have no idea how Panasonic have done this but they have and it works

So yes I do highly recomend the G6

I can record 2.5 hrs on a cheap 32gb card and I stll get stunning images off the G6

 

I feel like you and I must be taking crazy pills. :)  We seem to be the only people who believe these cameras are wonderful for 95% of shooters. The G6 and GH2 are both still absolutely superb cameras. I have had ZERO problems pulling a key from either of them. I think the hype that has come with these RAW hacks is really distracting folks from some great cameras on the market. 

 

I wouldn't recommend the Magic Lantern RAW hack for a newbie at all. Total advanced user stuff and frankly overkill. a G6, GH2, or even some of these Sonys can offer a great chroma key-ready camera. 

 

$4,000 gives you plenty of options for stable, quality-assured cameras.

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Jiban, just in case you don't understand the issues from the beginning...

 

The generic term for green screen (or blue screen) is chromakey.  It means you "key" out a color (chroma), like a keyhole, and now you can see what is behind it (the chroma/color).  

 

In order for this to work, the software must go through the image, pixel by pixel, and determine if each pixel is the chroma you have selected, green in your case.  Naturally, every pixel will not be an exact green.  Some will be dark, some light, some may be bluish from the lighting, or reddish, etc.

 

In the software you can set the lattitude of what is, or is not, a green.   This leads to problems.

 

To key out the bluish green around an edge of the screen, you may pick up a bluish-green part of someone's shirt, and then that ends up being keyed through.  

 

Green, may reflect off the screen, onto someone's hair, and then that gets screwed up.

 

IN SHORT, GREEN SCREEN, IN PRACTICE, iS DIFFICULT TO DO VERY WELL.

 

Optimally you need

 

1. A large screen

2. A long distance between screen and subject to prevent spill

3. A well lit screen

4. A well list person, lit in a way that will match the visuals you'll key in.

 

If you think about this stuff, you'll realize that the better the camera knows a green from a not-green, the better it can apply a key.  Most video cameras throw out a lot of color information in compression, 4:2:0 (instead of 4:4:4) that one doesn't notice much in most circumstances BUT is a serious problem for green screen work.

 

YES, you can pull a good key with 4:2:0 video cameras, like the G6, but it is MORE difficult than a camera that doesn't compress the video image in that way.  I don't know whether it would be better to invest in a better green screen and lighting and use a G6, or invest in a camera that does 4:4:4, maybe $4,000 used and go cheap on lights, etc.  There is NO hard answer.  

 

In short, I am giving background behind what mtheory is saying--no one in their right mind would choose a 4:2:0 camera to do professional level green screen work unless they had a perfect studio setup.

 

The ML setup works because the RAW video contains 14bits of true color information at every pixel location.  Yes, the workflow is monstrous, but if you end up spending all your time trying to light your screen screen to get a good image, and can't, with a 4:2:0 camera, you might not think it so bad ;)

 

Almost every camera your friends will own is probably 4:2:0.  Borrow on and try it first.  Don't invest money in any camera until you go through chromakey workflow at least once to understand the issues I've explained.  Then you'll know what is, or is not important to you.

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green screen with a 4:2:0 is NOT hard at all you dont need a 4.4.4 camera - a Canon or Panasonic camera will work just fine

have a look at this big green screen video I directed and shot on 4:2:0 cameras no problems at all.

 

I have directed alot of big expensive green screen videos for Major Record companies over the past 20 years

 

http://www.youtube.com/watch?v=vtkbNHe5vSc

 

http://www.youtube.com/watch?v=dMXfD-vQ5ng

 

 

Take it from me with green screen the most important thing is the lighting NOT the camera !

Make sure you light your set and subject correctly and you will save loads of time in post as good lighting = good pulls and easy keying , which means less time in post.

So practice alot with your set up and test before you do something for real!

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I have done greenscreen compositing with my DVX100, with my XH A1 and nothing since, just 'tests'. Both must be considered inferior by any means compared with modern cameras - and modern software.

 

Back then it was Ultimatte and/or Primatte, plugged in After Effects. Today I would highly recommend to try the very easy Keying-Filter within FCP X, should you happen to have access to it. To achieve visually perfect results, you have to reveal the 'advanced' options, but once you allow the new background's colors to counteract spill (tool: 'Light Wrap') and 4:2:0 edges (instead of complementary tint and much edge feathering), you will love it.

 

Being in no way an expert for chroma keying, I still think the spill issue doesn't get much better with 4:4:4. Reduce spill by seperately lighting the greenscreen (as recommended above or in every greenscreen tutorial), that's more than half the battle. 

 

exotics wrote:

 

Optimally you need

 

1. A large screen

 

 

 

Arguable. The larger the green background, the more spill, almost unavoidable. A very rich broadcaster in my country built a green hell of a news studio, and it looks terrible. I followed the advice of Maschwitz in his DV Rebel:

Make the green background as small as possible, make it a green towel, light it as little as possible (but as evenly as possible, outside, with an overcast sky, you will get the least spill). Let it just barely cover your foreground object, cut away everything else with garbage masks. Even allow an occasional hand or foot to stick out, a few frames of roto won't hurt you, but the key will be better.

 

Of course, this is not an option for a 'broadcaster' or someone who needs to isolate an ensemble of dancers.

 

Testing greenscreen techniques is cheap and easy. Multi-talented cats move and have whiskers. Let your cat play with a laser pointer in front of a green background. Then comp it into your slightly tilt-shifted kitchen and let yourself be hunted. The incredible shrinking EOSHD user.

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Axel brings up an important technique, using the green screen for only the area directly behind your subject and hard-cutting out the rest.  That usually needs good software. Again, I am NOT saying that you can't green screen with 4:2:0, only that it is something you should understand about the process.  The software that you use is very important, and can be expensive.  No easy decisions.  You can also see there is plenty of space between Andy's subject and the green screen background.   I want to point out, other experts, that we're talking to a beginner here. I'm DEFINITELY impressed by what you've done, but you know what you're doing and have a deep understanding of the tools involved.   :)

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BMCC is 4:4:4. I have keyed 4:2:0 footage successfully ( 5D2 H264 ), but it takes me about 3x times longer, plus some shots got spoilt because my DOF was too shallow and the edges of actors were too blurry. With BMCC, the sensor is much smaller and your actors' contours will always be very sharp. You can always add DOF in post, but taking it out is impossible. Plus, with 4:4:4 you will be able to adjust exposure and the 2.5k will provide a better pixel sensitivity for your keyer. 

 

In fact, if you absolutely, definitively want the best key in the world, shoot your actor in portrait mode...that should give you an equivalent of a 4K RAW 4:4:4 vertical resolution...the absolute top notch image for keying and compositing into something else.

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green screen with a 4:2:0 is NOT hard at all you dont need a 4.4.4 camera - a Canon or Panasonic camera will work just fine

 

 

Yes, it works fine. No one is saying its impossible, but the OP is asking for the best option. Working "fine" and being the "best suited" are not the same.

 

To be clear: I've also pulled some excellent keys with a 4:2:0 camera, but there are times that I had to work around limitations (subject's feet spill, for example), where I'm sure I would have had less hassle on a 4:4:4 image. I know on my older 4:2:2 camcorders there was slightly more leverage to fix things like that, and shooting a RAW image even more so. 

 

The G6 looks like a great camera, don't get me wrong- I'm still considering what to get next and its atop my list at the moment... but you've got to be realistic about what it is and what it isn't. 

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In fact, if you absolutely, definitively want the best key in the world, shoot your actor in portrait mode...that should give you an equivalent of a 4K RAW 4:4:4 vertical resolution...the absolute top notch image for keying and compositing into something else.

 

Flipping the camera 90 degrees is actually great advice! Obviously it will only work if you are filming one person who isn't moving side to side all that much, but if you are doing that you technically don't even need 4:4:4 anymore!
I did this recently with a GH2 because the image is now 1920 pixels high (almost double the 1080 vertical pixels normally recorded). That means I can scale it down in post more than 50% - in fact, to fit this comp it only needed to be be 30% of the original size, once it was flipped and placed in the scene. By doing this you are not only effectively smoothing out edges of your key, but you are actually condensing the CbCr color spaces together and making your 4:2:0 image have the same effective color sampling resolution of a 4:4:4 image (scaling down the CbCr values will give the same amount of definition as one recorded with higher fidelity). 

The nice thing about recording in 4:4:4 directly is that you don't need to scale anything if you don't want to, but as we mentioned- you CAN pull just as nice of a key out of a 4:2:0 camera, just with more work and more limitations to work around!

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 it only needed to be be 30% of the original size, once it was flipped and placed in the scene. By doing this you are not only effectively smoothing out edges of your key, but you are actually condensing the CbCr color spaces together and making your 4:2:0 image have the same effective color sampling resolution of a 4:4:4 image (scaling down the CbCr values will give the same amount of definition as one recorded with higher fidelity). 

 

Though recording vertically is a good advice, your explanation is faulty. By condensing the color information you get worse color accuracy. This is all about spacial resolution.

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Though recording vertically is a good advice, your explanation is faulty. By condensing the color information you get worse color accuracy. This is all about spacial resolution.

 

I'm not sure we're talking about the same thing. 

According to how color subsampling is supposed to work (http://en.wikipedia.org/wiki/Chroma_subsampling), 4:2:0 has 2, and 0 defined cbcr pixels for every 4 Y ones. If you are reducing all of them in post, you are ending up with the same color resolution as 4:4:4 unscaled. 

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