Tiffen T1 - I am impressed

[Bob Grant]

Originally Posted by John Peterson

I am undecided whether to try that filter on my EX1 (weekend after next) for a Dance Recital I have to shoot. Another poster seemed to feel that it would impart a green caste to the footage that is impossible to remove.

Did you experience that for the stage production you shot with the filter?

Thanks,

John

I suspect I'm that "other poster".

You can remove the overall green caste by white balancing the camera. What you cannot compensate for is that the T1 changes the spectral response of the red channel. My closest understanding of what that causes is a shift in the primary chromaticity of the camera's red channel. One complaint I've read from other users is this causes a change in skin tones which is subtle but very hard to impossible to grade out. No surprises there. These outcomes are quite predicable from the published spectrographs of the T1 filter. You also loose some light throught the T1 filter.

I shoot mostly stage productions and I have both the T1 and the 486 filter. The 486 from B&W has no impact on the visible portion of the spectrum. Again the published data shows this very clearly, the difference between the T1 and 486 is chalk and cheese. Not only does the T1 introduce a problem with the cameras colorimetry it doesn't cut quite enough of the near IR to totally remove the problem.

On the downside the 486 is a more expensive filter and being a dichroic it does introduce a color shift at low angles of incidence. This is covered in the warning from B&W about the uses of this filter at wide angles. In the real world unless you're shooting as wide as the EX will go and mostly white or pale walls you'll never notice it. Shooting wide with pale backgrounds is very unlikely when shooting stage productions. Getting as much light as possible and not having to do a manual white balance are two positives for the 486 if you want the best possible image quality and can afford the extra cost.

As I said before I have both filters. I knew from day one the T1 was no magic solution to the problem, there simply isn't one, but I bought it anyway just in case I struck a shot where I'd have to use it in preference to the 486. That's quite some time ago and it's only been on the camera while I ran some tests. The 486 has never been off my own camera nor have the 486s ever come off the the other two EX1s or two EX3s we have apart from the rare times a WA adaptor has been fitted.

If you've got a T1 and are shooting a stage production it's certainly going to be better than no filter. Get a tungsten light (an ungelled stage light will do) and use that to white balance the camera. Stage lighting is all over the place color wise anyway so you'll not notice any issues. The magenta shift it the blackout cloth is hard to not notice.

[Darren Ruddock]

I think sometimes because we are looking for stuff you notice it more. I'm not dismissing the T1's flaws but have clients ever run up to you after you have given them the product and said "Hey I know you have been using a T1 and I hate the picture."

I personally don't hugely like the down converted picture from HD-SD that I do via Compressor but anyone who doesn't know loves the picture. Just so easy to become over critical because we all work with this stuff and see it everyday!

[Marcus Durham]

Originally Posted by Bob Grant

You can remove the overall green caste by white balancing the camera. What you cannot compensate for is that the T1 changes the spectral response of the red channel. My closest understanding of what that causes is a shift in the primary chromaticity of the camera's red channel. One complaint I've read from other users is this causes a change in skin tones which is subtle but very hard to impossible to grade out.

I had problems a few months back with someone with a spray-on tan. It's long been known that such fake tans can result in slight colour shifts on camera, but the T1 did leave a green tinge on highlights after white balance that was most annoying. I ended up having to do some spot colour correction for the close ups.

I'll state again, I had white balanced.

That said it was the lesser of two evils as the person in question was wearing clothing that was black to the eye but not to the EX1.

The T1 only goes on when I see a problem and comes straight off again afterwards.

[Andrew Stone]

Thanks Bob for your informed post on the matter.

-Andrew

[David Arendt]

I am thinking situation where there is no time to white balance, only a take a preset. Will the green color cast the T1 is leaving be easily correctable in post ? Has anyone already tried it ?

[Joe Oliverio]

Here is a link to a YOUTube video we made which shows the affect of the T1 filter on the EX1 and EX1R. The problem seesmt o have been pretty much fixed in the EX1R and I don't use the T1 with it.


YouTube - EX1 and EX1R and Tiffen T1 filter test.wmv

[John Peterson]

Originally Posted by Bob Grant

I suspect I'm that "other poster".

You can remove the overall green caste by white balancing the camera. What you cannot compensate for is that the T1 changes the spectral response of the red channel. My closest understanding of what that causes is a shift in the primary chromaticity of the camera's red channel. One complaint I've read from other users is this causes a change in skin tones which is subtle but very hard to impossible to grade out. No surprises there. These outcomes are quite predicable from the published spectrographs of the T1 filter. You also loose some light throught the T1 filter.

I shoot mostly stage productions and I have both the T1 and the 486 filter. The 486 from B&W has no impact on the visible portion of the spectrum. Again the published data shows this very clearly, the difference between the T1 and 486 is chalk and cheese. Not only does the T1 introduce a problem with the cameras colorimetry it doesn't cut quite enough of the near IR to totally remove the problem.

On the downside the 486 is a more expensive filter and being a dichroic it does introduce a color shift at low angles of incidence. This is covered in the warning from B&W about the uses of this filter at wide angles. In the real world unless you're shooting as wide as the EX will go and mostly white or pale walls you'll never notice it. Shooting wide with pale backgrounds is very unlikely when shooting stage productions. Getting as much light as possible and not having to do a manual white balance are two positives for the 486 if you want the best possible image quality and can afford the extra cost.

As I said before I have both filters. I knew from day one the T1 was no magic solution to the problem, there simply isn't one, but I bought it anyway just in case I struck a shot where I'd have to use it in preference to the 486. That's quite some time ago and it's only been on the camera while I ran some tests. The 486 has never been off my own camera nor have the 486s ever come off the the other two EX1s or two EX3s we have apart from the rare times a WA adaptor has been fitted.

If you've got a T1 and are shooting a stage production it's certainly going to be better than no filter. Get a tungsten light (an ungelled stage light will do) and use that to white balance the camera. Stage lighting is all over the place color wise anyway so you'll not notice any issues. The magenta shift it the blackout cloth is hard to not notice.

Thanks Bob,

I ordered a B&W 77mm #486 filter today. I won't even try the Tiffen filter. It's killing me not to use my EX1 for making SD DVDs of stage productions because they look so bad (visible only on CRT televisions) so for $152 it's worth it if the filter gets rid of the unacceptable CA that haunts the outlines of the dancers and actors on stage. As far as the brown that is supposed to be black, that's not even noticeable. But the colored ghosts around the edges of the performers I can't stand. So if the filter solves that problem, I'll be happy I spent the money.

Thanks,

John

[Dave Morrison]

That IR filter will not fix the CA problems you are having. Sorry.

[John Peterson]

That IR filter will not fix the CA problems you are having. Sorry.
=====================

So now over $200 worth of filters and I'll still have the problem?

This is why I stick to my vx2000 for stage productions.

John

[Dave Morrison]

Sorry to be the bearer of bad news, John. In my limited knowledge of optics, CA is caused by a lens' inability to focus all the primary colors at the same exact spot on the imaging surface (film, digital imaging chip....whatever). Mine has the same CA issue at full telephoto. An IR filter is only going to block IR wavelength light from contaminating your black subject matter. If it did anything to affect CA, it would be purely by accident. Again, sorry.

[Vincent Oliver]

You can get around the CA problem in both After Effects and Photoshop (Extended edition) see my thread here, I have posted a few examples too.

http://www.dvinfo.net/forum/sony-xdc...-question.html

[Bob Grant]

Originally Posted by Dave Morrison

That IR filter will not fix the CA problems you are having. Sorry.

Some very quick tests someone else conducted indicate it might. The longer wavelength of IR means it is refracted at a different angle and hence can cause what looks like CA. A quick test using a res chart with the 486 on and off showed less apparent CA with the 486 on. Same would apply with the T1 as well to some extent.
For certain it's not going to cure all the CA but every little bit helps.

[Anthony Nalli]

I've only just learned about the IR issue with the EX3. In a shoot I did last weekend I noticed excessive red, particularly in the clouds (see image). I was using built-in ND as well as a linear polarizer in a Cavision matte box.

Am I correct in assuming that this IS INDEED the EX's IR issue? I'm just about to order the Tiffen T1 77 mm which (from what I've been reading) is as close to the fix as I'll get. Right call?

Anthony

PS. It's already been suggested that it appears more like it needs a white balance adjustment but I had done one within the hour and it looked fine in the viewfinder.

[Dave Morrison]

To me, it just looks like the rosy hues of sunset.

[Anthony Nalli]

It was about 2:30 pm on a bright sunny day.