red& green screen

[Ram Shani]

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

[John Sprung]

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.

[Stephen Williams]

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

[Ram Shani]

thanks

 

so i go with day light lighting in the studio.

 

what is the recommend ASA to work with ?

[Chris Kenny]

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.

[DJ Joofa]

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.

[John Sprung]

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.

[Ram Shani]

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