Jump to content


Photo

red& green screen


  • Please log in to reply
7 replies to this topic

#1 Ram Shani

Ram Shani
  • Basic Members
  • PipPipPipPip
  • 735 posts
  • Cinematographer
  • isreal

Posted 09 July 2008 - 10:55 AM

hi

i am going to do big project with the red cam

it's all green screen(or blue)

any tip will be great

we are going 4k

the aspect ratio is 1:2.5

never worked with the red so any tip will be great

thanks
  • 0

#2 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 09 July 2008 - 02:44 PM

I'd expect green screen to work better than blue. The blue channel has more noise, the green channel has twice the photosites.



-- J.S.
  • 0

#3 Stephen Williams

Stephen Williams
  • Sustaining Members
  • 4708 posts
  • Cinematographer
  • Europe

Posted 09 July 2008 - 06:38 PM

I'd expect green screen to work better than blue. The blue channel has more noise, the green channel has twice the photosites.



-- J.S.


Hi,

The sensor is also partial to daylight, which is a bumber if your in a studio with rigged tungsten light.

Stephen
  • 0

#4 Ram Shani

Ram Shani
  • Basic Members
  • PipPipPipPip
  • 735 posts
  • Cinematographer
  • isreal

Posted 09 July 2008 - 10:16 PM

thanks

so i go with day light lighting in the studio.

what is the recommend ASA to work with ?
  • 0

#5 Chris Kenny

Chris Kenny
  • Basic Members
  • PipPipPipPip
  • 264 posts
  • Other

Posted 10 July 2008 - 10:51 AM

If a studio has installed tungsten lighting, you might consider tossing a filter on the lens to correct to daylight. A full CTB is going to lose you a couple of stops, though, so this isn't always a plausible option.

Red rates the camera at 320 ASA. Opinions vary. To get the cleanest image, you'll probably want to ignore the light meter and expose as high as you can go without unacceptable clipping. There are some nice on-camera tools to check this. In the build 16 beta, the raw display mode + false color exposure gives you enough information to push things right to the edge with reasonable safety.

Shoot your own tests, if at all possible.

And remember that the real-time video image generated by the camera isn't your final product; the camera records compressed raw sensor data. Pull the files into Redcine and play around with exposure and curves if you want to see what the camera is really capturing.
  • 0

#6 DJ Joofa

DJ Joofa
  • Basic Members
  • PipPipPip
  • 149 posts
  • Other

Posted 10 July 2008 - 11:19 AM

I'd expect green screen to work better than blue. The blue channel has more noise, the green channel has twice the photosites.



-- J.S.


In addition to color, many industrial-strength keyers, such as Primate and KeyLight, use the luma information to accumulate the silhouette of the foreground vs. background. Several hacks are used on the luma information to get to that stage.

Blue can have an advantage in outdoor shooting so that the key does not have to be perfect because people accept blue overtone on skin color and perhaps clothes, in outdoor setting.

One may force white balance to use co-efficients that don't boost blue gain as much so as to reduce noise if that helps in background / foreground separation.
  • 0

#7 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 10 July 2008 - 01:42 PM

Working in 4:2:2 (which, of course, is not a good place to be for keying), some people simply discard the green screen idea, and try pulling an old fashioned luma key. If the green is bright enough to make that work, you get a sharper matte. It seems to work a lot of the time.



-- J.S.
  • 0

#8 Ram Shani

Ram Shani
  • Basic Members
  • PipPipPipPip
  • 735 posts
  • Cinematographer
  • isreal

Posted 11 July 2008 - 12:31 AM

thanks all

i will do test next week will let you know.

the studio is just space so i can bring any light i want.

i will use green kino for the green screen,

and daylight kino for the foreground.

maybe put on then 1/2 cto or cts
  • 0


Technodolly

Metropolis Post

Gamma Ray Digital Inc

Willys Widgets

FJS International, LLC

Wooden Camera

Aerial Filmworks

Media Blackout - Custom Cables and AKS

CineLab

Visual Products

CineTape

Rig Wheels Passport

Ritter Battery

Glidecam

The Slider

rebotnix Technologies

Abel Cine

Opal

Tai Audio

Broadcast Solutions Inc

Paralinx LLC

Wooden Camera

Metropolis Post

Technodolly

Broadcast Solutions Inc

CineTape

Ritter Battery

Visual Products

Tai Audio

Abel Cine

rebotnix Technologies

Aerial Filmworks

The Slider

Willys Widgets

Rig Wheels Passport

CineLab

Glidecam

Paralinx LLC

Opal

Gamma Ray Digital Inc

Media Blackout - Custom Cables and AKS

FJS International, LLC