RED and Blue Filters

Frank DiBugnara · July 17, 2009

This has been mentioned in passing in past posts, but I'm looking for a definitive answer on the issue of blue filters.

We know that the daylight-balanced RED sensor can get noisy when forced into a tungsten situation. If I am in a situation where I am stuck in a tungsten world and feel as though I have the stop to take things at least part way to 5500K, which filter would be best? Has anyone else opted to do this?

Thanks.

David Mullen ASC · July 18, 2009

This has been mentioned in passing in past posts, but I'm looking for a definitive answer on the issue of blue filters.

We know that the daylight-balanced RED sensor can get noisy when forced into a tungsten situation. If I am in a situation where I am stuck in a tungsten world and feel as though I have the stop to take things at least part way to 5500K, which filter would be best? Has anyone else opted to do this?

Thanks.

Any amount of blue filtering helps, so use whatever is practical. A lot of people opt for the 80C filter, which corrects 3200K to 4400K and I believe loses 1-stop of exposure. If that's too much, try the 80D filter.

Though I've gotten away with 3200K shooting on the Red. The noise isn't that bad at 250 to 320 ASA... and it's been improved since the latest build and new color science upgrade.

Satsuki Murashige · July 18, 2009

Apparently, Schneider has come out with a new series of blue camera filters called CTB that work like the 80 series for balancing tungsten to daylight, but with much less stop loss. Looks ideal for use with the Red camera.

Check it out: http://provideocoalition.com/index.php/aad...er_ctb_filters/.

David Mullen ASC · July 18, 2009

Apparently, Schneider has come out with a new series of blue camera filters called CTB that work like the 80 series for balancing tungsten to daylight, but with much less stop loss. Looks ideal for use with the Red camera.

Check it out: http://provideocoalition.com/index.php/aad...er_ctb_filters/.

The amount of stop loss relative to the amount of blue filtering is the same for the Schneider CTB series as it is for the 80 series. There is no magic bullet to get around that. Nowhere in the article does it say that an equal amount of blue correction on the CTB filters requires less stop loss than an equal amount on the 80 series.

The 1/2 CTB and 80C filter are very similar in amount of stop loss and amount of correction to daylight.

Art's point in the article that you don't need the full 80A filter to correct the Red enough to balance the RGB levels.

John Sprung · July 20, 2009

The amount of stop loss relative to the amount of blue filtering is the same for the Schneider CTB series as it is for the 80 series. There is no magic bullet to get around that.

Yup, it's the same for anybody's filter that uses dyes. The problem arises at the molecular level. Anything that attenuates a significant amount of red and green also cuts a lot of blue, too.

-- J.S.

Satsuki Murashige · July 21, 2009

Ok, good to know. Thanks!

Do you guys see any advantage to using the CTB filters over the 80 series filters then?

David Mullen ASC · July 21, 2009

Ok, good to know. Thanks!

Do you guys see any advantage to using the CTB filters over the 80 series filters then?

Less confusing?

John Hoffler · July 21, 2009

Less confusing?

lol

I wish I had utilized an 80 filter on a music video I recently shot on RED... I balanced for 3200K (at 320ISO) shot at a t1.3/2 (for shallow DoF/roll focus effects) and that made my shadows (in the t .5/.7 range) noisy as hell! Learned my lesson... ^_^

Mike Thorn · July 21, 2009

I wish I had utilized an 80 filter on a music video I recently shot on RED... I balanced for 3200K (at 320ISO) shot at a t1.3/2 (for shallow DoF/roll focus effects) and that made my shadows (in the t .5/.7 range) noisy as hell! Learned my lesson... ^_^

What build did you shoot on?

Apparently with the new Build 20 colour science (and RedCine) you can go back and re-process footage, even from earlier builds, and get amazing results.

Apparently the noise floor drops significantly. I haven't seen any comparisons myself.

Ben Kufrin · July 21, 2009

Any amount of blue filtering helps, so use whatever is practical. A lot of people opt for the 80C filter, which corrects 3200K to 4400K and I believe loses 1-stop of exposure. If that's too much, try the 80D filter.

Though I've gotten away with 3200K shooting on the Red. The noise isn't that bad at 250 to 320 ASA... and it's been improved since the latest build and new color science upgrade.

I too have used the 80C/D filters under tungsten because I didn't like the noise I saw when I balanced the camera to 3200K and that I believe was build 17. I definitely do not like sacrificing the stop in tungsten when using the 80 correction filters but it rendered a cleaner "negative". Here's a posting by Leandro Marini illustrating some of my results when we graded the raw files at Local Hero Post on the Scratch after I exposed under tungsten with 80C filtration. Hope this helps.

http://localheropost.squarespace.com/journ...ies-part-2.html

BEN KUFRIN

Director of Photography iatse local 600

Venice, CA

David Rakoczy · July 21, 2009

I too have used the 80C/D filters under tungsten because I didn't like the noise I saw when I balanced the camera to 3200K and that I believe was build 17. I definitely do not like sacrificing the stop in tungsten when using the 80 correction filters but it rendered a cleaner "negative". Here's a posting by Leandro Marini illustrating some of my results when we graded the raw files at Local Hero Post on the Scratch after I exposed under tungsten with 80C filtration. Hope this helps.

http://localheropost.squarespace.com/journ...ies-part-2.html

BEN KUFRIN

Director of Photography iatse local 600

Venice, CA

Ben? Ben Kufrin???? How the heck are you man? LONG long time no see.... hope all is well with you! Great to see you (here). :)