Red problem !

[Piotr Wozniacki]

BTW, Tom's pictures above remind me of another phenomenon I'm not sure whether somehow related to the IR problem: while the blacks of fabrics (and alike) materials tend to show brownish, I've noticed that black and "cold" materials (like polymers, or glossy leather) often adopt a somewhat greenish hue (I'm NOT talking about the frame extremities, coincidence angle side-effect of the IIR cut filters; also, this happens in daylight as well, while the IR contamination is most pronounced with tungsten lighting).

Anyone noticed that?

[Steven Thomas]

Originally Posted by Piotr Wozniacki

Tom, I dare say the colour differences between the two pictures are much more than one of the 2 cameras having the IR contamination problem; I'm sure you're aware of that :)

Yes, the first one is a lot cooler and the second on the warm side.

[Alister Chapman]

Tom (edited.. originally said Steve), I would say the difference between your two shots is down to 3 things. The white balance difference (as has already been discussed), the fact that the cameras are shooting at different angles relative to the sun and the different colour matrices the two cameras use. If you colour balance the images in Photoshop they both come out looking remarkably similar, including the blacks. IR contamination is much less of an issue under sunlight anyway.

[Steven Thomas]

Originally Posted by Alister Chapman

Steve, I would say the difference between your two shots is down to 3 things.

Thanks Alister, but these are not mine... LOL
They were posted by Tom roper.

I agree about IR in daylight is not that much of an issue.

[Alister Chapman]

OOPs my apologies Steve! This thread is just toooooo long :)

[Dave Morrison]

Originally Posted by Steven Thomas

Thanks Alister, but these are not mine... LOL
They were posted by Tom roper.

I agree about IR in daylight is not that much of an issue.

Steven (or anybody), would gelling a tungsten lamp to raise the color temp possibly reduce the IR contamination problem? For example, if you were shooting an indoor interview and there was a lot of ambient light getting into the room, would adding a CTB or 1/2 CTB reduce the IR any at all?

[Steven Thomas]

Dave, I imagine it would, but by how much, I'm not sure.

It would be great for someone to set up a test tunsgsten with increments of CTB and compare the results.
Or just plain tunsgsten bulb (white balanced), then switching lights to daylight balanced bulb (white balanced).

If this has already been tested, I would be interested in the results.

[Dave Morrison]

I'd be willing to try it if I can get some time in my buddy's studio some time soon. I'd be testing this with a Lowel Rifa light so I'm not sure what effect the diffuser panel would have. When I first got this softbox, I noticed right away that the black baseball hat my subject was wearing came out as a very dark brown so I guess the diffuser panel doesn't block IR to any appreciable degree. I might test this with one of the FL heads that can be swapped on the Lowel light too......if I can get my hands on one! ;-)

[Piotr Wozniacki]

Originally Posted by Dave Morrison

Steven (or anybody), would gelling a tungsten lamp to raise the color temp possibly reduce the IR contamination problem? For example, if you were shooting an indoor interview and there was a lot of ambient light getting into the room, would adding a CTB or 1/2 CTB reduce the IR any at all?

First of all, I agree with Alister (and others) that in sunlight, the IR is not a problem, really.

For indoors, my Sony LED light (5600K) also allows to avoid it almost completely, but it's ugly on human faces.

I'll repeat my question; is the greenish cast to "cold" blacks (equally seen here in sun and tungsten light) also related to the IR contamination ? Did anyone notice that?

[Pierre Legault]

I think I mentioned it before in this tread, I took a picture of a Black metal chair covered with black matérial.
The tissue is brown instead of black but the metal parts legs and backrest came out perfectly black

So personally I would think that the greenish issue you are mentioning has no common ground with the IR problem

[Piotr Wozniacki]

Originally Posted by Pierre Legault

I think I mentioned it before in this tread, I took a picture of a Black metal chair covered with black matérial.
The tissue is brown instead of black but the metal parts legs and backrest came out perfectly black

So personally I would think that the greenish issue you are mentioning has no common ground with the IR problem

When I give it another thought, perhaps you're right it's not so much metal, but other "specific" black materials that tend to adopt the green tint I mean; for instance my desk chair covered with nylon "net", or PC loudspeakers' nylon grills...

[Dean Harrington]

Originally Posted by Ryan Avery

Here are the stock codes and pricing for the True-Cut IR 750;

68-121044 4" x 4" True-Cut IR Filter $295.00
68-121056 4" x 5.65" True-Cut IR Filter $395.00
68-121057 5.65" x 5.65" True-Cut IR Filter $550.00
68-121059 5" x 5" True-Cut IR Filter $550.00
68-121066 6" x 6" True-Cut IR Filter $595.00
68-121077 77mm True-Cut IR Filter $250.00

All prices are list prices in USD. Check with a dvinfo sponsor for discounts.

Ryan Avery
Schneider Optics

It appears the 77mm (stock #: 68-121077) is not being sold at this point?

[Steven Thomas]

What's the latest on the 77mm IR-CUT filter for the EX1?

Is there a good solution that does not have the green shift issue at wide?

[Leonard Levy]

Tom- Literally 15 seconds with the wanky color adjusting tools in "Preview" on the web create a perfect match on those 2 stills.

[Alister Chapman]

Just watched a BBC TV show (Strictly come dancing) and noticed that the Judges on the show all appeared to be wearing very brown looking suits. Looks like IR to me and this is a top end HD studio shoot.