hvx green screen question,

Jason Miller · February 24th, 2007, 03:43 AM

ok this is getting old, two camera, same results, was in the green screen room yesterday with my camera, I tryed all the settings I could thing of, I was exactly 3 meters from subject, who was 15 feet from the screen. she was in focus, best results were still detail -3, but I still have those damned black and white halos around her. is this camera able to get a clean key?

its driving me nuts, please help

http://www.wafflefilms.com/greenscreencolorchannel.tga

http://www.wafflefilms.com/greenscreenredchannel.tga

http://www.wafflefilms.com/greenscreenbluechannel.tga

http://www.wafflefilms.com/greenscreengreenchannel.tga

Jason Miller

Jason Miller · February 24th, 2007, 04:20 AM

has anyone delt with this halo before? its a white and black line around the subject in front of a green screen, its seen mainly in the red and blue channel. if you've had this halo please tell me how you got rid of it. I have to have this figured out soon, I'm shooting a major project over the summer, and I have to have this figured out.

Sam Jankis · February 24th, 2007, 07:22 AM

Have you tried shooting in 720?

I've shot a handful of blue and green screens with the HVX and I've never seen this (but always in 720).

Jason Miller · February 24th, 2007, 12:21 PM

no fianl product always in 1080 so I shoot in 1080, this was 1080i/24pa

Jason Boyce · February 24th, 2007, 12:42 PM

It looks like the back edge of the subject is out of focus and picking up some of the green light from the screen. I'd bet that's what's causing your halo.

Plus your shutter speed looks pretty slow, blurring movement. You might want to speed it up to get crisper shots, that would make keying movements easier.

Jason Miller · February 24th, 2007, 01:27 PM

come on people it is not a focus issue, the shot with the woman is in perfect focus, exactly 3 meters from the camera. I shot it over and over again to find the focus, every setting from 2.5 meters to 3.5 meters there is something else going on with this camera. and it is a camera thing not a green screen thing, as I also show it with the screen lite is several ways, bright, dull, in each focal lenght, with each detail setting.

so what else in the camera can be played with, if everyone can check there 1080 greenscreen footage to see if these halos are there.

from everything I heard about this camera, 2 to 5 keys and its perfect, but these lines arnt effected by the alpha, so no matter how close I get the matte, te lines are still there. i'm honestly at a lose,

Marlon Torres · February 24th, 2007, 03:27 PM

I was bored and had to kill 10 minutes so I played with one of your screens... keyed out nicely for me...but then i again, it is just one frame...

http://www.citizencine.com/films/celestie/chromakey.png

Mike Schrengohst · February 24th, 2007, 04:39 PM

We did this on our PC using After Effects and zMatte
from
http://www.digitalfilmtools.com/zmatte/

http://www.motionzonehd.com/files/fo...eying_test.jpg

Jason Miller · February 24th, 2007, 08:48 PM

both of these have the black halo on it. although they do look pretty ok, they still look like keys, and if they look like keys it isnt going to work.

although I'm looking into zmatte for shake. cant seem to get the install to work but I'll get it.

Jason miller

Jeff Kilgroe · February 24th, 2007, 10:34 PM

Jason,

I haven't had a chance to revisit my scene files I use for greenscreen or to shoot another test. This new set of pics does look to be much more in focus than the previous image. But something about it seems off, even looking at the detail on her outfit, something doesn't look right to me.

I'm a little puzzled about the halo, I'll have to get some time to set the HVX on a tripod and test a few things, not sure how quickly that will happen though, I'm kinda busy on another project right now. But I think whatever it is that doesn't look right is playing a role here. The other issue you still have is a large amount of spill from the screen. I'm surprised to see that much spill if your subject is 15ft away. Also, do your halos seem to be affected if you move the camera further away?

Jason Miller · February 25th, 2007, 02:57 AM

well she's about 15 feet from the green curved walls, but she's standing on a green floor, but the floor isnt lit so the spill isnt from it. I've actaully got the key pretty much done, with a few tricks I've picked up working with beta, dv and hdv, placing a color matched plate under portions of the outer edge of the alpha, with a switchmatte and a hell of a lot of overs. but these tricks arn't needed with 16mm or 35mm, and frankly they shouldnt be needed with 4:2:2 hd,

by the way I think what your seeing is the detail settings, set to neg 3, the designers of the camera had a funny idea that adding edge lines one every edge would make the shot look better, unfortionatly when you remove the luma from the green channel you get cartoon like lines. I'm still thinking this is the problem I'm facing. maybe I need to go to neg 7. which is the lowest detail setting.

Jason Miller

Mike Fix · February 25th, 2007, 06:13 PM

Quote:

Originally Posted by Jason Miller

both of these have the black halo on it. although they do look pretty ok, they still look like keys, and if they look like keys it isnt going to work.

although I'm looking into zmatte for shake. cant seem to get the install to work but I'll get it.

Jason miller

I think the reason they look like keys is because they weren't lit for the backgrounds they were placed in front of.

Mike Schrengohst · February 25th, 2007, 07:38 PM

True, plus they were from a .jpg still.
it is much harder to key an element to look
realistic when everything is in motion.
The light angle, key and backlight placement
is what sells a shot. Just getting an exposure
of a subject against a green wall is only
20% of the challenge.

Jason Miller · February 26th, 2007, 08:05 PM

I've been examining the footage I just shot, and I thought of something that I've never thought off before, it looks like these halos may be some sort of black and white shifting from right to left, as it seems to always be worse on the right side, and slightly inside the subject, and better on the left side, but the halos are slightly outside the subject.

its sort of like the red bleed all zenith tvs seem to get on their 4th birthday. but with black and white rather than red.

any ideas on this new theory?

Jason Miller

February 24th, 2007, 04:39 PM	#23
Mike Schrengohst Major Player Join Date: Apr 2006 Location: Dallas, TX Posts: 355	We did this on our PC using After Effects and zMatte from http://www.digitalfilmtools.com/zmatte/ http://www.motionzonehd.com/files/fo...eying_test.jpg __________________ Mike Schrengohst dvd.pro@verizon.net

February 24th, 2007, 10:34 PM	#25
Jeff Kilgroe Major Player Join Date: Jun 2003 Location: Golden, CO Posts: 681	Jason, I haven't had a chance to revisit my scene files I use for greenscreen or to shoot another test. This new set of pics does look to be much more in focus than the previous image. But something about it seems off, even looking at the detail on her outfit, something doesn't look right to me. I'm a little puzzled about the halo, I'll have to get some time to set the HVX on a tripod and test a few things, not sure how quickly that will happen though, I'm kinda busy on another project right now. But I think whatever it is that doesn't look right is playing a role here. The other issue you still have is a large amount of spill from the screen. I'm surprised to see that much spill if your subject is 15ft away. Also, do your halos seem to be affected if you move the camera further away? __________________ - Jeff Kilgroe - Applied Visual Technologies \| DarkScience - www.darkscience.com

February 25th, 2007, 07:38 PM	#28
Mike Schrengohst Major Player Join Date: Apr 2006 Location: Dallas, TX Posts: 355	True, plus they were from a .jpg still. it is much harder to key an element to look realistic when everything is in motion. The light angle, key and backlight placement is what sells a shot. Just getting an exposure of a subject against a green wall is only 20% of the challenge. __________________ Mike Schrengohst dvd.pro@verizon.net

February 24th, 2007, 03:43 AM	#16
Jason Miller Regular Crew Join Date: Jan 2007 Location: san francisco ca Posts: 28	ok this is getting old, two camera, same results, was in the green screen room yesterday with my camera, I tryed all the settings I could thing of, I was exactly 3 meters from subject, who was 15 feet from the screen. she was in focus, best results were still detail -3, but I still have those damned black and white halos around her. is this camera able to get a clean key? its driving me nuts, please help http://www.wafflefilms.com/greenscreencolorchannel.tga http://www.wafflefilms.com/greenscreenredchannel.tga http://www.wafflefilms.com/greenscreenbluechannel.tga http://www.wafflefilms.com/greenscreengreenchannel.tga Jason Miller

February 24th, 2007, 04:20 AM	#17
Jason Miller Regular Crew Join Date: Jan 2007 Location: san francisco ca Posts: 28	has anyone delt with this halo before? its a white and black line around the subject in front of a green screen, its seen mainly in the red and blue channel. if you've had this halo please tell me how you got rid of it. I have to have this figured out soon, I'm shooting a major project over the summer, and I have to have this figured out.

February 24th, 2007, 07:22 AM	#18
Sam Jankis Major Player Join Date: Jun 2006 Location: St. Pete, FL Posts: 223	Have you tried shooting in 720? I've shot a handful of blue and green screens with the HVX and I've never seen this (but always in 720).

February 24th, 2007, 12:21 PM	#19
Jason Miller Regular Crew Join Date: Jan 2007 Location: san francisco ca Posts: 28	no fianl product always in 1080 so I shoot in 1080, this was 1080i/24pa

February 24th, 2007, 12:42 PM	#20
Jason Boyce Regular Crew Join Date: Apr 2006 Location: San Francisco, CA Posts: 77	It looks like the back edge of the subject is out of focus and picking up some of the green light from the screen. I'd bet that's what's causing your halo. Plus your shutter speed looks pretty slow, blurring movement. You might want to speed it up to get crisper shots, that would make keying movements easier.

February 24th, 2007, 01:27 PM	#21
Jason Miller Regular Crew Join Date: Jan 2007 Location: san francisco ca Posts: 28	come on people it is not a focus issue, the shot with the woman is in perfect focus, exactly 3 meters from the camera. I shot it over and over again to find the focus, every setting from 2.5 meters to 3.5 meters there is something else going on with this camera. and it is a camera thing not a green screen thing, as I also show it with the screen lite is several ways, bright, dull, in each focal lenght, with each detail setting. so what else in the camera can be played with, if everyone can check there 1080 greenscreen footage to see if these halos are there. from everything I heard about this camera, 2 to 5 keys and its perfect, but these lines arnt effected by the alpha, so no matter how close I get the matte, te lines are still there. i'm honestly at a lose,

February 24th, 2007, 03:27 PM	#22
Marlon Torres Major Player Join Date: Apr 2005 Posts: 230	I was bored and had to kill 10 minutes so I played with one of your screens... keyed out nicely for me...but then i again, it is just one frame... http://www.citizencine.com/films/celestie/chromakey.png

February 24th, 2007, 08:48 PM	#24
Jason Miller Regular Crew Join Date: Jan 2007 Location: san francisco ca Posts: 28	both of these have the black halo on it. although they do look pretty ok, they still look like keys, and if they look like keys it isnt going to work. although I'm looking into zmatte for shake. cant seem to get the install to work but I'll get it. Jason miller

February 25th, 2007, 02:57 AM	#26
Jason Miller Regular Crew Join Date: Jan 2007 Location: san francisco ca Posts: 28	well she's about 15 feet from the green curved walls, but she's standing on a green floor, but the floor isnt lit so the spill isnt from it. I've actaully got the key pretty much done, with a few tricks I've picked up working with beta, dv and hdv, placing a color matched plate under portions of the outer edge of the alpha, with a switchmatte and a hell of a lot of overs. but these tricks arn't needed with 16mm or 35mm, and frankly they shouldnt be needed with 4:2:2 hd, by the way I think what your seeing is the detail settings, set to neg 3, the designers of the camera had a funny idea that adding edge lines one every edge would make the shot look better, unfortionatly when you remove the luma from the green channel you get cartoon like lines. I'm still thinking this is the problem I'm facing. maybe I need to go to neg 7. which is the lowest detail setting. Jason Miller

February 26th, 2007, 08:05 PM	#29
Jason Miller Regular Crew Join Date: Jan 2007 Location: san francisco ca Posts: 28	I've been examining the footage I just shot, and I thought of something that I've never thought off before, it looks like these halos may be some sort of black and white shifting from right to left, as it seems to always be worse on the right side, and slightly inside the subject, and better on the left side, but the halos are slightly outside the subject. its sort of like the red bleed all zenith tvs seem to get on their 4th birthday. but with black and white rather than red. any ideas on this new theory? Jason Miller