IR filters with Red and double linear polerizers...

[hunterrichards]

Has anyone successfully used an IR filter with their Red (for IR photography)?

specifically the hoya r72?

Looks like it would be fun to use.

Also somewhere along the same lines:

I just took two linear polarizers and stacked them, when you rotate them both to the correct spots, you almost cut ALL of the light, sort of like a variable ND, has anyone else experienced this?

 

[Brent J. Craig]

The R72 would be fun to test, since we have already proven that the Red One is sensitive to infrared. The exposure times would be long, but I bet it would be cool!

I have found that when stacking polas there is always a weird color shift. Maybe I need to try a couple of really good Schneiders or something.

 

[hunterrichards]

I have found that when stacking polas there is always a weird color shift. Maybe I need to try a couple of really good Schneiders or something.

Yeah, I see the shift. But the interesting thing is that when they are both at the right angle (and everything goes black), it looks like everything is illuminated with a black light or something.

 

[Tico Llaurador]

I just took two linear polarizers and stacked them, when you rotate them both to the correct spots, you almost cut ALL of the light, sort of like a variable ND, has anyone else experienced this?

The still photography world has known the Singh-Ray variable ND filter for a while now, which does just what you describe here. I have one in 77mm and have used it on the RED with still 35mm photo glass. Works great. Haven't tried it behind any other filter, though.

Thanks for that gorgeous IR shot. Looks great!

http://www.singh-ray.com/varind.html