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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Using a blue filter?

A

Al Curran

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Any suggestions in which CTB filter to use to help out with the noise in the blue channel on RED?

I hear Scnheider Optics might be coming out with a filter designed specifically for RED?
 
Zakaree Sandberg said:
there really isnt an issue anymore if you know how to light properly.
I shoot tungsten all the time. never have had an issue!

i usually shoot asa 200-250 when shooting tungsten.
Click to expand...

I and many others still have all sorts of problems when shooting Tungsten. Weird splotchy noise shows up. Zakaree, how are you avoiding this?
 
It's all a compromise.

First off, always shoot 4k unless absolutely necessary.
Secondly it's all about the ratio of how much and what kind of information / light.

The more light you feed it, with in reason, the more information the camera has to work with. More information means a more intelligent Digital White balance.

Lighting with the WYSIWYG off of a 17"LCD gets many a DP arrives at something like this histogram:
histo_nono.tiff


This is not in my opinion a good green screen histogram. It is under tungsten lights with no filtration.

After speaking and discussing we made a few changes that gave us this histogram for the same subject and framing:

histo_bing.tiff


Again, under tungsten light with no filtration. Move a few lights, open up a little, shift your WB is all it takes.
The second keys better. Plus make sure your lighting is done well.

That being said, I feel the "cleanest" images come from feeding it daylight, but just feed it "enough" tungsten and you should be in business.
 
Cinewalt said:
I and many others still have all sorts of problems when shooting Tungsten. Weird splotchy noise shows up. Zakaree, how are you avoiding this?
Click to expand...

Lighting properly is number one.

Another trick is setting asa to 200-250.. this is basically the same thing as adding the filter (except its free and works like a charm)

I have not had an issue with noise in a long time.
 
Zakaree Sandberg said:
Lighting properly is number one.

Another trick is setting asa to 200-250.. this is basically the same thing as adding the filter (except its free and works like a charm)

I have not had an issue with noise in a long time.
Click to expand...

i thought changing the asa is just changing metadata?

or does the change in asa cause you to use more light?
 
It is meta data. Zak is basically saying feed it 1/2 a stop more light than the 320 ASA tools are telling you to. Again, tungsten is fine so long as you give it "enough."
 
Zakaree Sandberg said:
Lighting properly is number one.
Click to expand...

I think you mean lighting "well" or "a lot." Here's the problem. A well balanced image has highs, mids, and lows... and those lows are still going to be "underexposed," which in my experience shooting tungsten reveals the nastiness.
 
Cinewalt said:
I think you mean lighting "well" or "a lot." Here's the problem. A well balanced image has highs, mids, and lows... and those lows are still going to be "underexposed," which in my experience shooting tungsten reveals the nastiness.
Click to expand...

well.. properly... whatever word you want:)

basically you need enough light that the blue channel wont freak out in the darks. make room for a little bit of crushing in post.
 
For Greenscreen the 80C/D is a must to protect the shadow detail. In 4k/3k its not an issue with enough quantity, but 2k@RC36 for high-speed goes from 2GB/min to 400MB/min. At that data rate the noise will rear its ugly head in a contrasty tungsten lit scene.

For Red Jobs I rent productions my 80C/D Filters and Tru-Cut. Might be a good way to make alittle $$.

Goodluck
 
Schneider Optics New CTB Filters

Schneider Optics New CTB Filters

Schneider Optics has recently come out with a set of filters they call CTB, available in 1/2 (equivalent to an 80D), 1/4 and 1/8th strengths, specifically to combat these issues.

I have attached a copy of their press release about these new filters. So far, we've filled two orders for customers, but do not yet have them stocked on our shelves.

Their press release shows the list prices, but if anyone would like a quote, I'd be happy to write one up, just let me know.
 
MiguelOrtega said:
http://provideocoalition.com/index.php/aadams/story/red_and_green_screen/P1/
Click to expand...

Hehe November 2008? Looks like someone needed to read REDUser earlier.

We were commenting on filtration for Green Screen immediately after LART
and Jim Arthurs did a great set of camera tests around the exact same time:
http://www.reduser.net/forum/showthread.php?t=7454

I would say "Just shoot 200-250asa and you'll be fine" isn't completely accurate. Yes your blue channel will be fine, but now you've lost a stop of light in your red and green channels.

Use HMIs or filter for blue. That'll get you the best result and least noise. After all if you're shooting on a green screen you probably are 20 feet from a rental house full of lights. It's not like you're going to have to break out a generator or find yourself short on gear.
 
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