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Marc Poirier
chroma keying cameras
on Nov 1, 2008 at 4:36:37 pm

Hi everyone,

I have heard about a new technology where a camera with a special lens and special background would create a perfect keyed background instead of tradtional blue/green screen keying..

where can I get more info on that technology.

thx.

Marc.



Thanks!

Markyyyy


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Bob Zelin
Re: chroma keying cameras
on Nov 1, 2008 at 4:47:09 pm

you write - "special background "

It's called a GREEN SCREEN. Perfect keys from a camera occur from perfect lighting. I dont' care what miracle product comes out - if a scene is poorly lit, you will never ever ever ever get a perfect key.

That's why lighting guys make more that anyone else on the set.

Bob Zelin




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Marc Poirier
Re: chroma keying cameras
on Nov 1, 2008 at 5:04:00 pm

I understand your point... but there is a technology out there where there is a ring of sensors on a lens that allow for keying in "not perfect" environments, or in places where space is a factor..

if a technology can be more efficient, why not check it out...

Marc.



Thanks!

Markyyyy


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Marc Poirier
Re: chroma keying cameras
on Nov 1, 2008 at 5:37:38 pm

this is what I was talking about... still not sure how efficient it is.. but worth checking it out..

http://www.datavideo.us/ckl-100.html?category_id=19&search_category_id=19&t...

regards,

Marc.



Thanks!

Markyyyy


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Bob Zelin
Re: chroma keying cameras
on Nov 1, 2008 at 9:17:08 pm

I know Datavideo well (although I did not know this particuar product). Datavideo has demonstrated low end chroma keying at the last 2 NAB shows with their piece of crap switcher. They have a motorcycle setup at the NAB booth, and people in the booth can hop on the motorcycle, and take a picture (with a fan blowing your hair), against a moving background (using a green screen). They use their DVD+R recorder (the MP-6000) to give visitors a copy of their "experience" on the motorcycle.

It's super low end stuff, and compared to Ultimatte, etc. its as low end as you get. After going to this booth at NAB, I actually specify the MP-6000 as a DVD recorder all the time, as it's the last of the professional stand alone DVD recorders (ever since Pioneer stopped making the LX-1). But most of Datavideo's products are pretty terrible quality. The DVK-100 is their stand alone chroma keyer. It is what it is - it's not professional gear. But great for a wedding or sweet 16 !

Bob Zelin




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Vince Becquiot
Re: chroma keying cameras
on Nov 1, 2008 at 9:53:24 pm

I have to agree here, if that's the same as what I've seen at NAB, it basically chokes the matte until the talent drops to the ground. I'm sure some people wouldn't know the difference, it depends on what you are looking for, no miracle though.

Vince Becquiot
Director | Editor

Kaptis Studios
San Francisco - Bay Area


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Marc Poirier
Re: chroma keying cameras
on Nov 2, 2008 at 12:32:32 am

thanks Vince... so with 2 unanimous comments, I am not gonna go with this product :)

Will keep the old fashion way works like a charm :)

Marc.



Thanks!

Markyyyy


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Marc Poirier
Re: chroma keying cameras
on Nov 2, 2008 at 12:30:04 am

Ha ha ha... not sure they'd love that comment but might be helpful for their developers :)

thanks for the feedback.. that's what I was looking for..

Marc.



Thanks!

Markyyyy


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Jason Jenkins
Re: chroma keying cameras
on Nov 2, 2008 at 1:32:46 am

That's a ripoff of the Reflecmedia chroma key system. I have the Reflecmedia Chromaflex system and it works quite well. No background lighting is necessary.

Jason Jenkins

Flowmotion Media

Video production... with style!


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Marc Poirier
Re: chroma keying cameras
on Nov 2, 2008 at 2:00:16 am

Thanks jason for the input..

even though they seem to be using the same type of technology, there seem to be a general acknowledgment that the 1st one is not good.. since you are using one (and probably looked at the datavideo one, what makes this one much better over the 1st one...

it looks quite impressive.. at least they have a video to show how it works..

what happens when you light the subject .. does it affect the screen lightness?

can you give me an approx price for this product?

what type of camera are u using with it?

thanks..




Thanks!

Markyyyy


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Jason Jenkins
Re: chroma keying cameras
on Nov 3, 2008 at 2:33:32 pm

Hi Marc,

I think the others were commenting on the Datavideo brand in general, not specifically on their reflective chromakey system. For all I know it could be just as good as the Reflecmedia one. Lighting the subject won't affect the chroma background unless you blast it with some serious wattage. They don't recommend using it outdoors. As I recall, the Reflecmedia Chromaflex system with the 7'x7' portable backdrop was about $2,300. I've used it with a DV camera and a DVCPro50 camera. It doesn't make keying foolproof ––you still have to know how to use the system, but it does make it easier and faster because you don't need to light the background.

Jason Jenkins

Flowmotion Media

Video production... with style!


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Marc Poirier
Re: chroma keying cameras
on Nov 3, 2008 at 3:02:28 pm

Thanks for the info.. sometimes we need to shoot in places where space is an issue and being able to gain the 3-4 feet of extra space is sometimes good...

will look into it..

regards,

Marc.



Thanks!

Markyyyy


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Mark Suszko
Re: chroma keying cameras
on Nov 3, 2008 at 9:02:55 pm

I was pretty sure he was talking about reflecmedia when I read the first post. Reflecmedia works, NFL uses it, from what I hear. But it has up and down sides. The down sides include:

Price. The cloth is just really expensive, especially in larger sizes. The cloth contains retro-reflective glass beads that bounce the ring light back towards the lens. You might be able to simulate the same thing with scotchlite fabric or road paint, but it will be way more expensive than latex flat chroma blue or green. I can wrap an entire studio in chroma blue or green fabric or paint for the price of an xtra-large sheet of this cloth. The price of the cloth is what held this system back from becoming a huge success with great market penetration. At the same time keying software has improved so dramatically that you can do way better with blue or green cloth now.

But because the whole principle of the thing is to only bounce back a keyable blue or green directly back to the lens, if you want to key a much wider area, the ring lite becomes a limitation as it only shoots light straight ahead. The sides of your shot will get less and less light from the lens ring illuminator the wider you go, also the farther back you go. A regular chroma background can be at almost any distance or angle and still work if it's lit ok.

The ring light is also a problem if you want to put a teleprompter in front of your lens, it reflects in to the splitter mirror and the mirror attenuates the ring's output as well.


Meanwhile, software gets more clever. My wife's imac isight camera comes with a remarkably good live keyer effect in it that uses DIFFERENCE KEYING. You turn on the keying with a mouse click, step out of the camera shot for a second so it can grab a clean plate of the room behind you, then you sit back down and bam, the imac can put you live into most any static or moving backdrop you choose. Some included with the mac were the Eiffel tower, a tropical beach, and a roller coaster car in motion.

I expect to see more of the difference keying trick appear in consumer and prosumer apps.

I think it was some MIT work I saw online where they have a method of capturing the entire frame of a shot in perfect sharpness and then let you roll the depth of field control anywhere you like, like you had a tilt-shift lens in post.

Here's my blue-sky idea: I can foresee using z-depth cues for future keying technology. For example, we know our image sensors can see IR wavelengths and today we add filtration to the sensors to screen it out... but what if we remove the filtration and/or had an extra sensor in the same optical path sample outlines in IR to determine z-depth, illuminating with a camera-mounted IR source, perhaps IR laser LEDs, and then apply that data as an alpha channel layer in real time in the camera? Any flat wall of any color could become a chromakey type wall, or no wall at all, you just need a foot or two difference in distance between the actor and anything else to select it for the z-depth. Not only that, but, if you extend this to a logical conclusion, you have a ONE-LENS LIVE 3-D TV CAMERA as well, if you can keep the various items in z-axis separated and tracked with their z-axis metadata. Is 10-bit enough to hold all that? Maybe? IR is not as sharp as visible wavelengths, so the key you cut using IR might be a little softer around the edges than a conventional chromakey. But I think edge detection and correction could be figured out by a clever coder.

I just want 1% of the gross for the idea.






"Oh, you wanted to RECORD that?"


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