IR Contamination..any further forward??
 

Hi,

Had a shoot yesterday which involved an interview. A black chair and some background elements looked brown, dreaded IR!!

So are we any closer to knowing which filter is best?

True Cut 750 or the 486?

Many thanks,

Darren

Hello Darren,

The 486 is the filter recommended by Schneider.

I have one on my EX-1 & HPX-500 and do not see any green issues.

The HPX-500 needs it just as much as the EX-1 btw.

Hi Tim,

Interesting as some people report the issue of the green vignetting while others don't. I'm wondering wether it could be down to which firmware you have?

Is it right I have to get the slim version of the 486?

Wish I got the 486.
I ended up getting the RedRockMicro Hot Mirror (Redrock microFilters) and it only cuts the IR a *tad*. Still very noticeable in certain situations.

This is what I read.
"It appears that the Sony EX cameras exhibit the same form of IR sensitivity that the Sony F35 and the Panavision Genesis do. Therefore the best filter for these cameras is not an IR Hot Mirror but instead a Tiffen IR ND non-Hot Mirror filter. This filter set was created for the F35 and Genesis. It is also less expensive than the Hot Mirror type filters such as the Formatts we sell for the RED.

Please note that different types of cameras and sensors require different type of filtration. The Formatts remain the recommended solution for the RED but the Tiffen non-Hot Mirror product is best for the EX1/EX3.

Art Adams over at ProvideoCoalition.com is doing an IR Filter Shoot Out to see how filters from three manufacturers work with the RED, F35 and EX Cameras."

Last I read the results Art were getting were not entirely valid. Some further work was in progress but I've not read anything since before NAB.

Schneider did have a new IR cut filter at NAB that Ryan showed me. It's an IR cut combined with a polariser. My understanding is the the addition of the polariser stops the green vignetting problem. Don't know anything more about it than that. Ryan did say he'd provide more information about it here but so far nothing.

Personally I'm quite happy just leaving a 486 on my EX1 however as I now have a .75 WA adaptor I'll need to rethink this.

Bob

I assume the IR + Pola has a 2 stop exposure loss?

Didn't think of that, yes, reading up elsewhere it seems a polarizer has a loss of around 2 stops. That kind of rules it out in many situations for me, darn.

I did tests with Art about a month or so ago. On the Ex-1 the only thing that really worked worth a Dxxx was the 486 which was great but vignettes green at wide angles.

We talked with tiffen and they are trying to make a dye based filter for Tungstun on the Ex, but haven't heard back form them yet. until then the 486 is the only game in town.

Rosco solution for IR ...
 

Rosco 4x5.650 (Panavision) TruColor IR Camera Filter was supposed to be reviewed. Has anyone received one? I know it works on RED ... will it work on EX1/3? The reason I ask is that the Rosco is clear ... not ND, not polarizer and not a hot mirror. It has Sharp cut-offs below 390nm and above 720nm to restore the balance of visible and invisible light reaching the camera sensors. This is what we need ... is it not?

From what I've read it's @ 680 to @ 700 where the EX is lacking.

Exactly - hence the question: anybody successul with the Schneider 680 ???

thanks ...
 

You are right on that David.

The Tru-Cut 680 is the same filter as the 486. The only difference is the 680 is designed for matte box use (either 4x4 or 5.65x4) and the 486 is 77mm screw-in. Other than that, they are identical in construction and performance. (correct me if I'm wrong Ryan) I have used the 680 and it works exceedingly well at removing IR contamination, but it does cause the slight green vignetting at focal lengths wider than 15mm. The 750 will NOT work on the EX. I believe that has been covered extensively in other posts.

The IRNDs (by Tiffen) will have some effect on IR contamination, but cannot be used with any other ND because the amount of dye in the filter is based on the level of ND needed. Therefore, adding ND (without adding dye) will add visible IR contamination since there isn't enough dye present to counter the amount of IR contamination. What this means is, you cannot use your built-in NDs on the camera, and you cannot use any other NDs unless they contain the dye if you want to correct the IR issue. This can add up to a MUCH more expensive solution than the 680/486, depending on how much ND you need, because you would need several of these filters. (or, if you just buy one heavy ND, limits your exposure options dramatically)

I am curious about the new filter Ryan showed at NAB... this is the first I have heard of it. I wonder if using a polarizer along with the 680 would have the same effect as this new filter with it built-in? (ie, polarizer behind the 680?) Ryan? Any thoughts on this? This would offer more flexibility if shooting at a longer focal length than 15mm, or needed all the light you could get and didn't want to lose a couple stops to the pola.

I did a test with the rosco. it worked very well at getting rid of red IR in black cloth. BUT, it has similar green vignetting on W/A lenses. Both with the EX-3 & the Red.