7D for chroma Keying??? or 5D or get another brand for this

S

sporty

Active member
I will be doing heavy green screening and I'm delaying to buy because I keep getting told to wait for the newest Dslr... I'm now down to 30 more days to decide and thinking about just preordering the 7D now.... What is my best solution for green screening in the 3000$ price range.... I want clean Keys with the sharpest edges for under 3000$. Does anything out there do uncompressed recording and out put in my price range??


Is the 7D compression and color space good enough??

Should I just stick with the 7D for the bang for buck or what do you guys recommend for under 3000???
 
for doing chroma keying, the hvx200a or hpx170 are the best prosumer cameras for pulling a key due to its 4:2:2 color space in the dvcproHD codec. but i have seen good keys pulled with 5d footage. but majority of a good key depends on good lighting and a solid green background. so if you've got a good lighitng/screen setup, then pulling the key shouldn't be that much of an issue. then it comes down to software. after effects with the keylight plugin is one of the best next to shake.
 
Well, the codec is at least as good as HDV, and the chroma subsampling is 4:2:0 just like HDV. If you want HD, you can't get anything better for under $3000.
 
The $3000 price range is really the limitation here. Without stepping up to about $7000, the 5D and the 7D would be the best bet, I think, basically because they make up the whole market.
 
For chromakeying which would rule?

a)canon HV40 - capturing uncompressed through Blackmagic Intensity card @ 4:2:2

OR

b)canon 7D - with its higher resolution but only 4:2:0 chroma
 
turdtoothless said:
For chromakeying which would rule?

a)canon HV40 - capturing uncompressed through Blackmagic Intensity card @ 4:2:2

OR

b)canon 7D - with its higher resolution but only 4:2:0 chroma
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Why do you think the 7D would have higher resolution than an HV40?

And if I was choosing between those two, strictly for keying, I'd say the uncompressed HV40 would probably be the better bet. 4:2:2 is way better than 4:2:0 for keying.
 
Barry_Green said:
Why do you think the 7D would have higher resolution than an HV40?

And if I was choosing between those two, strictly for keying, I'd say the uncompressed HV40 would probably be the better bet. 4:2:2 is way better than 4:2:0 for keying.
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better yet, blackmagic or nanoflash with the canon hf-s100 will get you around 800-900 lines of resolution, 4.2.2
 
NoahK said:
Got a pretty convincing argument for the 5D here:
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Yeah, but... I mean, come on... that guy's test had to be the easiest key test on earth. He had no hair and clean edges everywhere. Put up a blonde with hair blowing in the wind, with some lace and glass, and I think the disadvantages of an inefficiently-compressed artifact-potential 4:2:0 system are going to become obvious as versus an uncompressed 4:2:2...
 
I dunno- those are pretty tack sharp lenses. Sure I'd love to have both that and a RAW codec for $2700 but maybe it's just a little more fun to try something new.

Noah
 
Barry_Green said:
Yeah, but... I mean, come on... that guy's test had to be the easiest key test on earth. He had no hair and clean edges everywhere. Put up a blonde with hair blowing in the wind, with some lace and glass, and I think the disadvantages of an inefficiently-compressed artifact-potential 4:2:0 system are going to become obvious as versus an uncompressed 4:2:2...
Click to expand...

Ditto that Barry. I've been pulling a lot of keys lately and they have been exactly what you've described-platinum blonde models dancing with fans blowing and ghostly pale skin that will reflect green no matter how you light it. This guy's test is too easy.

With that said, you can pull a key off of a pretty lousy camera. Last footage I've worked with was off of an A1U which I consider crap. The secret is preparation. You have to learn how to use a lightmeter and/or waveform monitor. Then you have to direct your models and be careful with wardrobe.

If you're new to keying you won't learn this unless you get out there and shoot and try to key footage.
 
I've heard that Cineform Neo will interpolate the 4:2:0 footage into 4:2:2. Would this make a difference in pulling a better key?
 
From http://www.adamwilt.com/DV-FAQ-tech.html#colorSampling


Can I chroma-key with 4:1:1 / 4:2:0?

Yes indeed. Many early DVEs were 4:1:1 internally; plenty of digital boxes out there still are (such as the Panasonic WJ-MX50 and Sony FXE-series vision mixers, both of which chroma-key). As previously mentioned, BetaSP could be considered a 3:1:1 format in terms of component bandwidth, and BetaSP is used for chroma-key applications all the time. With some care, DV25 keys at least as well as BetaSP; read on... Part of the standard JVC sales pitch for D-9 is the superiority of 4:2:2 (which is true), and the utter doom and degradation that awaits you should you try to do anything -- including chroma-key -- with a 4:1:1 format (which is, shall we say, a wee bit exaggerated). But that doesn't mean that you can't do very satisfactory work in 4:1:1.
JVC had an excellent D-9 demo tape showing multigeneration performance comparisons of DV, D-9, and Digital Betacam; watch it if you can. Just be sure you take the hype with a grain of salt.
True, the chroma performance of 4:2:2 formats is superior to 4:1:1 formats, especially in multigeneration analog dubbing. But by the same token, 4:4:4 is as superior to 4:2:2 as 4:2:2 is to 4:1:1 or 4:2:0.
Where DV can get into trouble is that the coarse resolution of the chroma signal (only 180 samples per scanline in 4:1:1) leads to a very regular, "steppy" key signal, most noticeable on near-vertical edges or vertical edges where motion is present, especially if the codec's decompression simply replicates the chroma sample across the intervening pixels instead of low-pass filtering or interpolating between samples. The 4:2:0 sampling in 625 DV/DVCAM is somewhat better in this regard, but it has its own problems vertically, so there's always a tradeoff.

The single most important factor in good DV chroma-keying is low-pass filtering or interpolating the chroma prior to applying the keyer, so that the “steppy edges” are knocked off. Some codecs do a pretty good job of this by default (Avid DV); some can be set up for it (Matrox: [FONT=Courier New, Courier, monospace]Control Panel > Sounds and Multimedia > Hardware > Video Codecs > Properties > Matrox VFW Software Codecs > Settings... > Chroma Interpolation (YUV -> RGB)[/FONT]); with others you can add a filter (I have filters for FCP here).
Some people capture DV for chroma keying using an analog Y/C feed, since the analog connection prefilters and smooths the chroma.
The Matrox RTX.100 DV NLE board uses multi-tap resampling of DV's chroma to generate astoundingly good, crisp, finely-detailed keys in real time – so there is certainly enough information on DV's chroma for most keying purposes; the only tricky bit is recovering it intelligently!
Additionally, use the matte choker and/or matte feathering and smoothing controls of your keyer to round off the edges a hard-cut key signal gives you. I've had excellent results with After Effects Production Bundle's Color Difference key, and superb results also using the Chroma Keyer in Final Cut Pro 3. Using these tools I can make very clean and acceptable keys, certainly for hard-edged keying. Spill supressors (or “edge enhance” in FCP 3's Chroma Keyer) are essential in cleaning up any remaining chroma spill in the foreground video.
You may also find that layering different key signals gives you excellent results. I've used a heavily-choked chroma key to cut my main matte, but then add one or two luma, extract, or difference keys to define the edge detail that the chroma key can't get. Each luma key may only work for a small part of the image; it may lose the greenscreen background but also lose the interior of a similarly-bright face. However, it usually is able to get edge detail, because the edges of a person fall off in shadow or are picked out brightly by the rimlight, and the chroma key holds the interior matte that the luma key won't provide.
DV-aware keyers like dvGarage's DV Matte Pro (for After Effects or Final Cut Pro) do a great job of keying DV; if you're frustrated by the standard software keyers provided with your NLE or effects package, try an add-on keyer. I used to struggle with FCP's chroma key, even with my add-on chroma smoothing filter (or the ones Apple supplied starting in FCP 4.0), but DV Matte Pro is so much better (and easier to use) I almost can't compare it. I simply kick myself for not trying it out sooner!
John Jackman has some good examples of DV keying on his post-production pages at greatdv.com.
 
here are some tests Ive done with the 5D mark II.

Barry, if you thought the C47 guys test was easy...I raise you one ANIMATRONIC CAT.

I was blown away with its quality. It blew my old HVX200 out of the water even considering the H264 codec

I would assume that if the 7D's noise pattern is a little worse, but the bitrate of the H264 codec is higher than the 5D your looking at some very similiar results.

http://extranet.modea.com/hasbro/furreal/tests/ball_test.mov

(user is hasbro...pass is pawtucket)

(around 27mb, so let it load)

Chaz
 
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Matthew Bennett said:
The ultimate for chroma keying is an Andromeda modded DVX100A (...)
Click to expand...

Until you want HD resolution, that is. I guess the easiest way to find out would be to rent/borry a 5D or 7D for a day and stick something fluffy in front of a cheap screen. Software tools that have been developed to give fairly good results even to ugly mini-DV footage can only ease matters.
 
Good post Cjwolf.
Just to add to it, i used to do quite a bit of keying dv footage professionally about 10 years ago and definately found layering to be effective, especially in conjunction with masks in AE.
Also, i found with the horrible edges DV footage had. It was always better to key with a very loose feather to the edges. Spill supress the green and choose suitable (dark) background footage to key onto. I was lucky enough to be able to give input into what backgrounds could be used.
In all the keying i did with AE i was never as impressed as what a big box in the studio did with a live feed. It was really impressive. It was called Trinity. I used to run both feeds of footage through it and capture the footage out of it, it was that good.
Im now looking forward to pushing 7d footage.
 
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