slr vs video cameras for green screen

V

vivi

Member
Hello, newbie here and first post

Before i go on my first post i like to say hi and thanks to those who created these forums, they are extremely informative and saved me many trips to local stores., also iam actually a pro tools mac person, i am familiar with cameras but vaguely, i know i like the colors of teh canon slrs, more professional cameras like the fs with lotus adapters, arrie both ditigal and film, this is the look i like, using Prime zeiss and other lenses to the addition.

anyhow, i have been searching for a decent camera to shoot green screen, i read on the creative cow forums that its best to have a 4:2:2 equipped camera for starts, larger sensors and matching lenses, they say forget slrs.
I found it interesting that SLR users swear by them yet none of them shot clean greenscreen, if you look at the webisode 3 around 14:38 from "The great camera shoot out" series : http://www.zacuto.com/shootout
Then compare it to a EX3 on this green screen video test http://vimeo.com/14535353 its clear that the ex3 is the way to go with green screen, yet slr users claim with a little DOF and fast lenses you can pull greenscreen off like the ex3.

But my question remains the same, what is the base price for a camera rig to record clean greenscreen at the same time provide rich colors like a 5dmkii,Also, im asking new or old cameras, i read that older hdmi equipped cameras can get great results using a ninja 4:2:2 capture box, but BnH people will only suggest new cameras so i dont know which are equiped with hdmi etc.


Any advise appreciated
 
I might be thinking along the lines of Canon XF100, 50 mbps, 4:2:2.

Bought one for my school, might try to cadge a loan
 
If your're in the market at XF300 prices then you could consider, say the sony or Panny options with an external recorder. I was basing my suggestion on DSLR comparable pricing.
 
The software you use and your technique play a big factor in Pulling a clean key. Plug ins help a bunch. They aren't cheap but make it easier and cleaner. A bad key is very distracting and why do it if it looks fake.

The color space is a good start because the more information you have the easier pulling the key will be.

Also lighting is a big deal. If the key isnt evenly lit, especially directly behind the subject its going to be hard to pull. So think about these other factors as well as what you decide to shoot with.
I've used a HDV camera with fairly good results but everything was setup pretty darn good.

I dont know what your experience with green screen is, but if you don't know about all the other stuff you really should hit the web and do some research. It will save you a bunch of time.
 
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i've done green screen with my t2i with pretty good success. make sure you have a lot of light and its even on the background and it will work nicely for you.
 
i agree with all the comments about the technique, software, i got away with cheaper cameras, but for film like close up clear green screen according to the GREAT CAMERA SHOOT out i mentioned above not one SLR cut it clean, they used the best lighting possible, light meters, you name it, so if they can not get the real deal its got to be video right, 4:2:2, but the EX3 is 4:2:0 so im lost, its newer chip seems to pull gs off very well in the other link.

i cant wait till the RED scarlet price go as low as 2k, just cant find anything reliable for full HD shooting besides the Canon 5dmkii, yet its also not clean., unless one goes to a ninja recorder at 4:2:2 full HD, then again owners of the 5dmkii tell me the direct signal out of the camera via hdmi is not clean, even when your not in record mode.
 
I would recommend an hpx250 tethered to a Black Magic card so you are getting 10to bit 4:2:2 uncompressed. You don't want too shallow a DOF or you won't be able to read your tracking markers on the green screen.
vivi said:
Hello, newbie here and first postBefore i go on my first post i like to say hi and thanks to those who created these forums, they are extremely informative and saved me many trips to local stores., also iam actually a pro tools mac person, i am familiar with cameras but vaguely, i know i like the colors of teh canon slrs, more professional cameras like the fs with lotus adapters, arrie both ditigal and film, this is the look i like, using Prime zeiss and other lenses to the addition.anyhow, i have been searching for a decent camera to shoot green screen, i read on the creative cow forums that its best to have a 4:2:2 equipped camera for starts, larger sensors and matching lenses, they say forget slrs.I found it interesting that SLR users swear by them yet none of them shot clean greenscreen, if you look at the webisode 3 around 14:38 from "The great camera shoot out" series : http://www.zacuto.com/shootout Then compare it to a EX3 on this green screen video test http://vimeo.com/14535353 its clear that the ex3 is the way to go with green screen, yet slr users claim with a little DOF and fast lenses you can pull greenscreen off like the ex3.But my question remains the same, what is the base price for a camera rig to record clean greenscreen at the same time provide rich colors like a 5dmkii,Also, im asking new or old cameras, i read that older hdmi equipped cameras can get great results using a ninja 4:2:2 capture box, but BnH people will only suggest new cameras so i dont know which are equiped with hdmi etc. Any advise appreciated
Click to expand...
 
I've pulled a chroma key with my t2i as well. Took a bit of work to get it clean, but that was mostly a lighting issue. With good lighting, I've seen it done.

I'm not sure where you heard that "old cameras" output 4:2:2, as HDMI ports weren't standard on little cameras until a couple of generations ago. Even then, I think the low end cameras all outputted the same 4:2:0 that they record. But I could be wrong about that.

I've heard the GH2 is capable of 4:2:2 out the HDMI port, but its a current generation DSLR. And even then, it sort of garbles up the 4:2:2 signal into 4:2:0 (conspiracy theories are that Panasonic doesn't want folks considering this a replacement for a pro camera). There's a thread here somewhere describing how to record the HDMI out from the GH2 and then use some clever AVIsynth scripts to pull the 4:2:2 1080 24p footage out of the 60i 4:2:0 stream.
 
I think you'd like the GH2: it has the sharpest and cleanest image among the DSLRs, and with the hack it can record internally in a very nice codec
 
M. Gilden said:
I've pulled a chroma key with my t2i as well. Took a bit of work to get it clean, but that was mostly a lighting issue. With good lighting, I've seen it done.

I'm not sure where you heard that "old cameras" output 4:2:2, as HDMI ports weren't standard on little cameras until a couple of generations ago. Even then, I think the low end cameras all outputted the same 4:2:0 that they record. But I could be wrong about that.

I've heard the GH2 is capable of 4:2:2 out the HDMI port, but its a current generation DSLR. And even then, it sort of garbles up the 4:2:2 signal into 4:2:0 (conspiracy theories are that Panasonic doesn't want folks considering this a replacement for a pro camera). There's a thread here somewhere describing how to record the HDMI out from the GH2 and then use some clever AVIsynth scripts to pull the 4:2:2 1080 24p footage out of the 60i 4:2:0 stream.
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ive been told to find hdmi equipped cameras with decent sensors, old meaning DV tape

also in regards to gh2 post i really dont like the gh2 colors, bit washed out, not clean like Canon
 
When it comes to keying, the first question is "what do you consider an acceptable key?" There are hundreds of youtube videos (and posts on this site) where the shooter expressed total amazement at their stunning key - which often just looked like crap. My guess is some people are just amazed they glued two shots together.

I did a music video with a Canon DSLR and the keyed shots were a ***** (I've been lighting for stills and then video for something like 15 years and I know how to set up such a shot). The Canon gave me a lot of trouble due to aliasing - particularly with back or rim lighting to separate the subject from the screen, the aliasing just sort of grabs onto those areas as if they're unsharp masked. I had to soften specific bits of keys. Hair detail was so-so. I had no trouble with spill or separation and lighting was dead-on - strictly camera issues.

Currently I use an HMC-150 for this stuff which does much better. But the AVCHD compression can be tough; camera likes a LOT of light to hide the sorts of artifacts that are "tucked in" to normal footage but become very apparent on alpha channels. Also, it's not a full-raster camera but is up-rezzing the footage a bit, and I felt I was really seeing that when I zoomed in on a mask.

Shooting with either camera, the three main things I learned were:

a) Use a lot of light - daylight, not tungsten (the chip's cleaner at daylight). Lift your shadows with some fill and crunch back down when you actually composite the shot (which helps glue it all together).

b) Get all the image data you can - shoot 1080, daylight setting, faster than usual shutter and some decent DOF (like 5.6 or so). Triple check your focus. Bring a BIG HDTV and check focus with it if necessary. Get as few soft edges and blurs as possible - you can always add them back in.

c) Tighten up your post methodology - Mark Christensen's After Effects books have the most comprehensive system I've seen and he covers all sorts of bases & problems. His revisions to the AE5 book add some great advice on choosing the right green from your footage.

Not knowing the specs of every camera out there, I'd guess the newer HMC-160 may be the best balance of price and performance - it's a full raster camera, and you can output 4-2-2 (though only 8 bit) via HDMI to, say, a Ninja. Honestly, will you see much difference with a 4-2-2 recorder for keying? Atomos posts here and said they liked my suggestion of posting straight and ninja greenscreen footage for testing, haven't seen it yet though. Me, I'd upgrade from my 150 to the 160 before dropping a grand to record uprezzed footage.

This is a 100% green screen video - 80-some shots. Some nice, some so-so. We ran amazingly out of time due to makeup and wardrobe. Wish I could re-shoot some of these. But overall it does show what the 150 can do.

 
its funny, i totally agree with all you guys but in my first thread i posted videos already answering to all the possible green screen pit falls, the videos i posted contain tests with $8k lighting equipment, light testers worth as much as the cameras, professional color studios and using just about every decent SLR possible, later video cameras as well, if i i have to spent that much money i rather by a digital Alexa.

So while i agree lighting is a factor can you watch the videos and explain why the SLRs record UN CLEAN green screen, meaning hairs have to be cropped because of bleeding, i def agree youtube is loaded with cheezy videos but the two i got are professional tests.

ill check out the HMC-160 for now
 
Here's an extremely poorly lit green screen sequence shot with a GH2.

If they can make this work, I'd think a good key is totally doable.


EDIT: Right, I forgot you said you didn't like the Panasonic colors (personal preference I suppose). Still, this is 4:2:0 color space.
 
So far the winners are the EX3 and the Panasonic 150

7d vs Panasonic 150

Green Screen Camera Shootout: T2i vs 7D vs HPX 170 vs EX-3

Great camera shootout
[video]http://www.zacuto.com/shootout[/video]
 
M. Gilden said:
Here's an extremely poorly lit green screen sequence shot with a GH2.

If they can make this work, I'd think a good key is totally doable.
Click to expand...

The biggest flaw I see in this is the swimming, pulsing noise in the grey hood area of her shirt. That's a very well documented failing of Keylight's de-spill tools. the best way to avoid this is to get the best matte you can in the first section of the keylight controls and ignore everything else;

Dupe that layer and choke the matte in a bit and soften it; set the view to Matte - you'll have a black and white layer. Dupe it again and delete keylight (so your top layer will be your original footage with the screen visible) - then set the track matte of this layer to the choked layer. The three layers will then give you a comp with the tightest edge you can come up with, but the "insides" will be untouched by keylight. If you're seeing spill on the comp, clean it up with masked color correction tools (usually hue/sat will do the trick or some levels).

The one thing you may see when doing this is green showing through hair or motion blurred areas - if so, you'll need to mask these areas from the track-matted layer. Pre-render the comp (with whatever garbage mattes and cleanup needed) and you should be good to go.

One other thing that's worked well for me when keying DLSR or HMC footage - do your keying in 1080 and pre-render; but do your final shot assembly (and your final edit) in 720, bringing the keyed 1080 prerenders onto 720 background plates and reducing to fit. This really cleans up the look (if you're cool with a final output of 720 - fine for most music video and non-broadcast stuff).
 
Michael Carter said:
The biggest flaw I see in this is the swimming, pulsing noise in the grey hood area of her shirt. That's a very well documented failing of Keylight's de-spill tools. the best way to avoid this is to get the best matte you can in the first section of the keylight controls and ignore everything else;

Dupe that layer and choke the matte in a bit and soften it; set the view to Matte - you'll have a black and white layer. Dupe it again and delete keylight (so your top layer will be your original footage with the screen visible) - then set the track matte of this layer to the choked layer. The three layers will then give you a comp with the tightest edge you can come up with, but the "insides" will be untouched by keylight. If you're seeing spill on the comp, clean it up with masked color correction tools (usually hue/sat will do the trick or some levels).

The one thing you may see when doing this is green showing through hair or motion blurred areas - if so, you'll need to mask these areas from the track-matted layer. Pre-render the comp (with whatever garbage mattes and cleanup needed) and you should be good to go.

One other thing that's worked well for me when keying DLSR or HMC footage - do your keying in 1080 and pre-render; but do your final shot assembly (and your final edit) in 720, bringing the keyed 1080 prerenders onto 720 background plates and reducing to fit. This really cleans up the look (if you're cool with a final output of 720 - fine for most music video and non-broadcast stuff).
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Good advice- not my video though.
Its also very poorly lit, more turquoise than green, and not a color that is very well separated from the actress (her sweatshirt has a similar shadow color).
My point was that this worked at all!

If they could get a half decent result from this, a properly lit screen should be much better.
 
the tests show the room was properly lit, maybe the youtube video conversion looks like that but according to the light tests its accurate and these are the results anyone with these cameras will get after converting to youtube as well, and dont forget these poor green spills are there because of 4:2:0 so the damage can not be fixed but covered up.
 
vivi said:
the tests show the room was properly lit, maybe the youtube video conversion looks like that but according to the light tests its accurate and these are the results anyone with these cameras will get after converting to youtube as well, and dont forget these poor green spills are there because of 4:2:0 so the damage can not be fixed but covered up.
Click to expand...
I don't think we're talking about the same example. The one I pasted was not properly set up, and the video description even admits that. And wasn't using Youtube either. ;)
 
M. Gilden said:
I don't think we're talking about the same example. The one I pasted was not properly set up, and the video description even admits that. And wasn't using Youtube either. ;)
Click to expand...

gonna check out the gh2, someone at creative cow just recommended it for greenscreen as well, tooo bad canon is greedy
 
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