IR Discoloration at center of frame

[R Fogg]

Has anybody else experienced this? Wide Superspeeds (18 & 25) against backlight causes IR discoloration at the center of the image.

Anyone dealt with this before?

 

[Mitch Gross]

Looks like a flare. I can see the shape of the iris.

 

[R Fogg]

Yes I see that too mitch, in this case the "flare" always stays centered even if the camera moves, pans or tilts, so it is not a hard source flare. Reflection off of the olpf back into the lens?

Hard to beleive no one else has seen this given the ubiquity of superspeeds on red cameras. This is the second time I have encountered it. Different cameras & SS sets. Hmmm...

 

[Steve Freebairn]

Ryley,

Which hot mirror are you using? Is it on backward? I've seen some discoloring where the edges on a wider lens (wider than 25mm) looked discolored with the first Schneider Hot mirrors they released.

 

[R Fogg]

Hey Steve, they are using the Rosco IR Cut. I do remember seeing the early Schneiders fall off on the edges but this seems to be a different issue. I am not on set so not sure about the orientation of the hot mirror.

 

[Dominic Jones]

Reflection off of the olpf back into the lens?

That was my first thought.

I've shot a fair amount with supers on a Red and haven't seen this, however... Very interesting. What stop were you at? Also, what other filtration was in front of the lens?

Dom.

 

[ericyoung]

Hey Steve, they are using the Rosco IR Cut. I do remember seeing the early Schneiders fall off on the edges but this seems to be a different issue. I am not on set so not sure about the orientation of the hot mirror.

Rosco IR Cut filters aren't "mirrors", so their orientation isn't important according to an answer I got direct from Rosco. The side with the writing is the side with the coating and it is NOT protected by a second layer of glass so it is more delicate than other sandwiched IR filters.