Tiffen T1 filter on all the time?

[Piotr Wozniacki]

Originally Posted by Bob Grant

I have the same feeling, just looking at a red LED through it I can see how much it is attenuating the visible red part of the spectrum. By very crude measurements using the camera I'd say the loss is over 1 stop. By comparison the 486 shows no loss. The 486 stays on the camera.
Only reason I bought the T1 was to try it out and also to see if I could fit it behind my WA adapter.

Yes it IS attenuating the visible light spectrum, and yes - it DOES inflict considerable light loss.

Nevertheless, I find the T1 attenuation correctable much easier than the 486's green vignette, and as to the low-light capabilities - well... It usually so happens with me that the more I care for an event's colors being rendered truthfully, the better it's lit (more powerful stage lights, etc.).

All in all, my case is the opposite to Bob's: I used to have the 486 which I sold away, and now have the 77mm screw-in T1 AND its 4x5.65" version coming soon...

But keep it on at all times? Not at all!

[John Peterson]

I haven't had a chance to try mine out yet, but what problems do you suppose I will run into under stage lighting. What did you set the white balance to?

John

[Bob Grant]

Originally Posted by Simon Wyndham

I could be wrong, but I felt that on the last shoot I did that the T1 made peoples faces a bit pasty. Again, it could have just been the light and I need to use it a bit more to be sure.

My understanding is that skin is a fairly complex thing. Not only is the outer layer reflecting light but the blood itself is reflecting deep red and IR which can penetrate through the skin.

What the T1 filter is doing is altering the response of the red channel sensor. White balancing does not correct this. Technically speaking the 486 filter gives more accurate color reproduction than the T1. Plots of filters similar to the T1 show this, interesting that Tiffen do not provide plots of the T1 whereas B&W do for the 486 and a warning about using it at wide angles.

I had hoped to get the T1 tested using the right equipment and I have gotten as far as finding a lab with the gear to do this. Unfortunately it's going to cost at least $400 and for me at least only confirm what I already know.

[David C. Williams]

Tiffen have shown a general spectral curve for the T1 vs a stock EX. It does cut pretty strongly across the board.

http://www.tiffen.com/userimages/T1_IR_Charts_SS.pdf

[Bob Grant]

Thank you so much for that David, that saved me either some money or a bit of jerry rigging.
For comparison the response curve for the 486 is on page 5 of this document:
http://www.schneideroptics.com/pdfs/...%20Catalog.pdf

[Piotr Wozniacki]

Originally Posted by Bob Grant

My understanding is that skin is a fairly complex thing. Not only is the outer layer reflecting light but the blood itself is reflecting deep red and IR which can penetrate through the skin.

What the T1 filter is doing is altering the response of the red channel sensor. White balancing does not correct this.

Yes - spot on again, Bob. Having also noticed what you describe, I simply developed a special PP for those situations where I MUST use my T1, whereby a (quite wide) skin color range is shifted a bit towards red.

This (plus a proper white balancing) makes my pictures quite neutral, while preserving the blacks (and dark greens, and dark blues)...

[David Esp]

I bought a T1 with little hesitation after a painful experience naively trying to match with a Z1. couldn't seem to get those browns to agree...

Any advice on good PP settings to compensate for T1 green tint would be much appreciated.

[Dean Harrington]

In conference or PR business shoots where the suits of the speakers seem to predominate in black ... I have noticed a difference between T1 and no T1. I've yet to have a skin tone problem but will check on that more closely.

[Don Greening]

This shot was done using a Lowell DV Creator Kit #55, which is of course, all incandescent. You'll notice that the area of the black drapes lit by the hair light creates more IR contamination than other areas. Thankfully, all it takes to fix this is one click in FCP's 3 way colour corrector.

I have had 2 Tiffen T1 IR filters on order for a while now.

- Don

[Marty Welk]

Don that Redish glow on the back curtain doesnt really bother the picture much, if i was analising this i would think that turning her into a red-head :-) would be the thing THEY would notice . In THIS case couldnt you just offset the light(s), solve the excess in the center, and kill the light reflection on the glasses in the same move?

that wouldnt cause me to stuff a filter on, thier skin tones look ok and all thier blacks other than her hair is ok. and the whole thing doesnt fall into the OMG look what happened realm. I can see it, but its not destroying everything at all.
If you can get them to smile, instead of worring about such excess technical stuff :-) why it wouldnt exist at all

[Don Greening]

We interviewed about 40 sets of people over a 2 day period in 2 different rooms. I was the card wrangler and hired 2 crews, including boom operators, to do the actual shooting with my gear. The lack of smiling was because of the subject matter: serious human rights violations. The frame grab was taken before that particular interview got underway.

- Don

[Marcus Durham]

My T1 arrived this morning after what feels like years of trying to get hold of one. Just done a few experiments.

Wow, it does fix the black problem. However the blacks still don't look quite as they look to the eye (or indeed my Z1). Highlights on them tend to lean towards being greenish. This is despite white balancing. The Z1 was coping just dandy.

Yes, there's also the loss of light. Not much but might be enough to be critical in marginal situations

Conclusion - It won't be staying on all the time as some people recommend. Instead I'll pop it on for interviews and specific material where I can see there is a problem. Otherwise you'll end up having to colour correct every shot to make it look more like the EX1 we know and love.

It's like any other filter I carry in the camera bag. I wouldn't leave the polarizer on all the time and I'm not going to leave the T1 on all the time either.

Would be interested to hear if anyone has a preset look for the T1.

[Piotr Wozniacki]

Markus,

There is no such thing as the "best" PP for the T1. The only thing I'm trying (with varying success) to incorporate into my own PPs (for those situations where I need to put the filter on) is some color correction (shifting the hue of skin tones towards red just a bit).

[Steve Browne]

Thanks everyone for all your comments and suggestions.
I'm going to stay away from the T1 as much as possible

Today I was filming this girl in a black t-shirt. I noticed the black browning up in the flip out screen and put the 486 filter on. This fixed the shot and it looks really good even though there's not much light
The full wide wide shots did not show any vignetting that I can see

But on this grab of a shot 1/2 zoomed in you can see a weird blue corner
There's a window just to her right so I guess the rays are coming in at a low side angle and hitting the filter
I remember now I didn't have the lens hood on so that may have caused it

Apart from that a great day!

[Dave Morrison]

Yep, sure looks like a light flare to me, too.