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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 :)

RED ND filter issues. . .

Stephen Pruitt

Stephen Pruitt

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Hi all. . .

I just got off the phone with BJ at Custom Supply and he informed me that there is a very serious issue using ND filters with the RED camera. According to him, people are seeing serious non-linear colorshifts within the image based upon the IR reflectance of the objects in the frame.

Since I'm about to begin shooting on May 20th, this is a disturbing development. How are the rest of you folks dealing with this issue? Most of our shooting will be outdoors.

Sincerely,

Stephen
 
Stephen,
There is a great thread on this issue.
http://www.reduser.net/forum/showthread.php?t=9412&highlight=hot+mirrors
I have a full set of Schneiders but haven't had a chance to test them out on my Red yet so I can't comment on personal experience. Sounds like there have been cases of color shift using high ND's and stacking ND's as well. People have been using some hot mirror filters to cut that IR coming through. There are also some soluitions that people have hinted at coming out at NAB. Schneider and Tiffen coming out with IR cutting filters.
But check out the thread as there are some great posts by fellows with much more insight that I. Hope that helps.
 
"Very serious" is a massive overstatement in my mind. The pollution is there, but it can be dealt with in the short term until companies put out hot mirror NDs.

Since you're not starting until the 20th of next month, you should definitely schedule a test with whoever is providing the cameras for you and judge for yourself.
 
Very Fuddy

Very Fuddy

I have used Schneider 1.2 and 1.8 NDs on numerous occasions and I agree with Brook that in "most" situations its a minor issue. That said, I plan to add IR filtration to my kit and hope to see solutions on the show floor at NAB. It will be nice to have truer blacks and save the hassle of color correcting out the IR pollution.
 
Thank you all for pointing out that thread. I originally ignored it because I assumed it was a thread on HOW to shoot using IR on the RED. . . which I would never do. Too funny.

Blair, what are you doing to add that IR filtration to your kit at the present time?

Thanks very much.

Stephen
 
Hot mirror = IR Filtration.

Read the thread, the thread is your friend. A good friend. A learned friend.
 
Ed Blythe said:
Read the thread, the thread is your friend. A good friend. A learned friend.
Click to expand...
Agreed. And like some great films, it will bring you through your full range of emotions. Laughter, tears, anger, excitement. :)
 
Every one of the 19 pages in that earlier thread has very valuable information.


I don't think it's a MAJOR issue, as in the camera will still run. However I'm not willing to stake my dayrate and reputation by betting that it won't effect a particular shoot. I've seen the IR pollution effect average no ND daylight shots, and I know from my own eyes that a hot mirror improved overall color definition in those situations.

It's very uncomfortable to sit in the edit suite with a client and have to explain that their product looks "off" because I left out a necessary piece of gear. Moral of the story, a hot mirror or IR cut filter will positively effect your imagery 90% of the time. It not worth the risk to shoot without it.
 
Mike Prevette said:
Every one of the 19 pages in that earlier thread has very valuable information.


I don't think it's a MAJOR issue, as in the camera will still run. However I'm not willing to stake my dayrate and reputation by betting that it won't effect a particular shoot. I've seen the IR pollution effect average no ND daylight shots, and I know from my own eyes that a hot mirror improved overall color definition in those situations.

It's very uncomfortable to sit in the edit suite with a client and have to explain that their product looks "off" because I left out a necessary piece of gear. Moral of the story, a hot mirror or IR cut filter will positively effect your imagery 90% of the time. It not worth the risk to shoot without it.
Click to expand...

100% Agree.

Emmanuel
 
Stephen, I did the same thing as you. I passed that thread for days thinking it was something on using IR to shoot at night. Not my scene so moved on. But there are some pearls in there. Chazmo nailed it. It does take you through the array of emotions. All I could think of was that coin that I dumped on Schneiders. But like many tales, this one seems to have a happy ending....the hot mirror.
 
Puddle of FUD

Puddle of FUD

I chose to jump in on this thread because I have had so many conversations with producers where partial or jumbled information has influenced their decision to not use the RedOne on their projects.

For those people who know their stuff, the specifics of the IR issues and the value in solving them is really not an argument anymore.

In my earlier post I said I was looking forward to seeing a solution on sale at NAB from Schneider, Tiffen, Rosco, etc - I have even emailed directly to sales reps at those companies asking for 4 by 5.65" glass filters with dressed edges that will fit neatly into the filter trays of my Arri MB-20Mk2.

For the record, IMO - IR suppression via filtration is an essential bit of kit for the RedOne. As soon as one of the major filter vendors offers an optically clean, well made solution I will buy one. In the meantime my bigger concern is losing gigs because the issue gets blown out of proportion.
 
Okay this is true and more then one manufacturer is working on it, trust me, they might talk as much as they want about RED but they are truly understanding the tremendous market of this cameras and are moving full speed ahead.

Info from my filter deal:

Red camera has problems with current ND filters, caused by the failure of the filters to reduce infra-red light as much as they reduce visible light. The result is that in daylight, where you need the filters most, you can get a severe magenta color shift.

Tiffen has a new line of filters that will be shipping in about 3 weeks that fix the problem, and Schneider is working on a solution. Tiffen also has a clear IR dichroic filter called a "hot mirror" that will reduce the problem when used with traditional filters. They currently make the filter in sizes to fit digital still cameras, and are working pricing for matte box sizes. I should have more information from both companies soon. Tiffen says, "any day now".

Traditional matte box filters are readily available, except for the 1.5 and 1.8 densities, but I am advising everyone to consider the new IRND filters, despite the fact that they are about 3 weeks away. They will be available in Panavision size first, in .3, .6, .9. 1.2, 1.5, 1.8, and 2.1 densities, in Tiffen's Water White glass.

Ciao
 
Agreed Blair.
Did we decide which filter was the way to go? Schneider 486 was it?
Cheers,
Harry
 
Apologies to Ira

Apologies to Ira

The irony of going to NAB to find something that blocks RED light. I couldn't make this sh*t up. :sick:

Seriously, NAB should be the perfect chance to compare options and despite the price I am a big Schneider fan.
 
I've done some testing.

A hot mirror would be a very good addition to your filter kit. In situations where there is a lot of IR it will improve your images a great deal.

Situations with lots of IR ? A hot day with bright sunlight behind you. Scenes lit with large open face tungsten units. Fire lit scenes, Hot objects...

The IR pollution can sometimes be observed with no ND, but the most dramatic effect will be when you are using heavy ND.

Different lenses seem to pass different amounts of IR also. I'm waiting for a hot day to test more.

Matt Uhry
www.mattuhry.com
 
Tiffen solution

Tiffen solution

Tiffen has announced IR ND filters. Availability in about 4 weeks. Call BJ at Custom Supply and he can order them for you at a great price. IR ND's beat using an extra filter just to cut IR.
 
So I went through that thread as well, but I'm trying to figure out why the IR filtering is not more aggressive in-camera...

For the moment, I'll assume I do not know the downside to more aggressive filtering in the OLPF/IR filter, rather than rant that somebody screwed up.

It's a drag though that for the time being, I have to guess if it's an issue with what I'm pointing the camera at in a given moment, and that IR filtering is not easy or simple for now.
 
I recall someone from Red saying they were unable to find a better IR-cut filter than what they have now with the required tolerances. They may have been looking for IR-cut, UV-cut and OPLF all in one? I don't know. Anyway that's up to them to work out; for now the camera is what it is.

I don't think the IR situation is too mysterious. Anything that has (or is illuminated by) a very low color temperature, may give you some IR trouble, and that is especially true if you are using ND filters. That means late afternoon and sunsets, tungsten lighting, open flame, glowing hot metal, lava, you get the idea. And if you are using heavy ND (more than ND.9) without built-in IR blocking, even normal sunlight has enough IR to start to become an issue.

At any rate, the IR filtering seems pretty easy and simple. Put a hot mirror filter in the front slot of the matte box. Done.
 
NateWeaver said:
So I went through that thread as well, but I'm trying to figure out why the IR filtering is not more aggressive in-camera...
Click to expand...

I seem to remember Prevette mentioning something about...physics. But I ain't dealt in that little monster since I was 16 so can't get into the specifics of it with ya...

Put one up front instead.
 
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