Hot Mirror/IRND/Mirror ND Filter Matrix [Parts 1-4]

[Trevor S Lawley]

what do you mean by contamination?
and, will long term contamination cause any other problems that you know of?

[ericyoung]

It's only ambient IR "colour" contamination of recorded images - it doesn't have any long term damage implications for the camera.

[Ricardo Simões]

Ryan Avery at Schneider optics has sent me a new formula of their Tru-Cut 750 Hot Mirror filter. Initial testing shows much less off axis color shifting, pretty much on par or better than the Tiffen or Rosco Hot Mirror. I still need to do IR filtering and combo testing but it looks promising. Formatt will also be sending me thier Hot Mirror. I also asked for and was provided Schneider's Sapphire Blue 1 & 2 filters. These filters are similar to 80d & 80c filters respectively. Some recent testing shows significant advantages using these filters with tungsten lighting. Especially the Sapphire 1 which only needs about 2/3 stop compensation but raises the effective color temp 1200 degrees and reducing chroma noise. Lastly, I have finally been bitten by the Pancro double reflection issue. I still feel the Pancros offer the best solution but caution should be exercised and combining them with other filters should be avoided whenever possible.

I'll try to get the more detailed new tests up as soon as possible but I do have a bunch of shoots coming up...
Stay tuned.

Hello Evin Grant
I have a question.
I would like know where you use the Hot Mirror filter. When i use 2 filters, like a ND 2.1 and a Hot Mirror, where should i use the hot mirror on the mattebox, close the lens or in the front?
Thanks for your help

[ericyoung]

Hot mirrors, because they are reflective should be the front filter to avoid unwanted light reflections bouncing back off another filter in front of it.

[Alexander Alexandrov]

Lastly, I have finally been bitten by the Pancro double reflection issue.

can you pls expand on this? were u using just one filter? or stacked with smth else?

so whats the final verdict as of today? still Pancro .9 1.2 1.5 IRNDs when used solo?

[Alexander Alexandrov]

Hot mirrors, because they are reflective should be the front filter to avoid unwanted light reflections bouncing back off another filter in front of it.

but i thought the hot mirrors / trucolorIR were to come after NDs, since they are to "balances the visible and infrared light" after NDs? pls correct me here.

also if a polarizer is used, where would it go in a stack?

[Pawel Achtel]

You can use one and only one hot mirror and it must be placed in front with the CORRECT side facing out. There must be no reflective filters or coatings downstream - only absorbtion filters. You must also use hard mattes as a well behaving boy would.

I haven't experienced any problems even with the unique Pancro ND 2.0

[Alexander Alexandrov]

You can use one and only one hot mirror and it must be placed in front with the CORRECT side facing out. There must be no reflective filters or coatings downstream - only absorbtion filters. You must also use hard mattes as a well behaving boy would.

I haven't experienced any problems even with the unique Pancro ND 2.0

so it is:

1 Pancro IRNDs as stand alone filters; they are to always go in front.
2 if standard NDs, then Rosco Trucolor or alike - always in front of them.
3 what about polarizer? where would that go? i'm assuming itcant be used in #1; what would be the order of it placing it in #2?

thanks!

[Lyndel Crosley, SOC]

Thanks for the post Evin. I just used the Tiffen Hot Mirror for my shoot in Japan. They were the bomb. Will post some RED stills once I get permission.

[Mike Thorn]

so whats the final verdict as of today? still Pancro .9 1.2 1.5 IRNDs when used solo?

Yes.

Or Formatt/Schneider when used in conjunction with other ND's.

Just as a side note...on my last shoot, I asked for a Rosco Hot Mirror. We liked it and it performed quite well, but we had a couple beefs with it (Colton Davie was my 2nd). First, it was a pretty rough filter; the edges were straight-ground and not round and smooth like a typical filter. It's also rather thin and fragile-looking. We also had a very difficult time determining which side was the reflective side. We were able to obtain the same reflections and colour shifts from both sides. So, we picked one side and stuck with it and got great results.

In the future, I'd like to try the Schneiders for sure, as I'm a big fan of their ND's.