OT: Tiffen's New T1 for EX Cameras

Jay Gladwell wrote on 10/16/2009, 6:54 AM

If you haven't heard, Tiffen has a new filter to correct the "far red" problem on the EX 1 and 3 cameras. The filter is now available from AbelCineTech. The cost is $69 U.S.

"The Tiffen 77mm T1 is a filter that removes most of the "far red" contamination, making blacks look cleaner. This is especially important on cameras with extended color gamut sensitivity, such as the Sony PMW-EX1 and EX3. Far red contamination is often confused with infrared contamination, which is a different wavelength on the color spectrum. A Tiffen T1 filter is suggested to be used on the camera lens as all time and under all lighting conditions."

This filter is light green, so white balancing is a must!

Hope this helps.

Comments

farss wrote on 10/16/2009, 7:08 AM

I might get one to test it out. I have reservations about using this filter. The only way I know to get the sharp cutoff required is to use a dichroic filter and then you have to live with the other problems that creates. This filter would seem to have a quite gentle rolloff and hence is going to cut red sensitivity.

One reason I'd still get this filter is I have a WA adaptor and going that wide with a dichroic is going to produce a more significant green vignette. On top of that the large dichroic filters to fit a matte box are friggin expensive!

Bob.

Jay Gladwell wrote on 10/16/2009, 7:58 AM

Perhaps I'm mistaken, but the prototype of this filter was tested by Leonard Levy in San Rafael, California. According to his results, the filter does the trick without the green vignette. According to Mr. Levy, "Because its a simple dye based absorption filter it doesn't vignette and treats light from all angles equally." In his opinion, he considers it to be the "perfect solution."

I simply wasn't willing to pay hundreds of dollars for a filter that corrected one problem only to create another (many times I have shoot wide angle).

Tomorrow night I have to shoot a black-tie affair (lots black tuxedos and black gowns) as part of a larger project. It's being held on stage under theatrical lighting, so we'll see how it does.

Former user wrote on 10/16/2009, 1:08 PM

I've been shooting a lot of green screen lately, and hopefully this solves the funky blacks I'm getting. And it's affordable. Yay!

farss wrote on 10/16/2009, 3:13 PM

You're not mistaken, you need to understand the physics.
A dye based filter will not create a vignette unlike a dichroic. They're two different kinds of filters.
Dichroics are layers of metal, they're like a set of notch filters. They're the only way to get a very sharp cutoff. The 486 does not affect white balance because it is not filtering light in the visible spectrum.
Dye filters are broad filters. The one in question looks green because it is attenuating red. Correcting this by adjusting WB means gain being increased in the red channel i.e. you're loosing sensitivity.

When I said test I did mean using an analyser to plot the spectral response The curves for the 486 are here:

http://www.schneiderkreuznach.com/tipps/uv-ir_cut_filter.htm

We have 5 EX cameras, all fitted with 486 filters that have never come off the cameras. These cameras have been used to shoot everyting included a series for broadcast and alongside F35s. No one, not once has found an issue with the green vignette. It's there of course but it's an over hyped issue.
This new filter will bring a different problem with it.
There's no perfect solution. Sony made a design decision with these cameras to improve red sensitivity and that's where the issue started from. The dye based filter undoes that. That's probably the best solution if you're shooting wide with plenty of light.

I'm the exact opposite, mostly shooting long with not much better than candlelight at times and red is the dominante color in a lot of what I shoot. Compared to what I paid for the camera neither of these filters are expensive.

Bob.

Jay Gladwell wrote on 10/16/2009, 3:33 PM

"This new filter will bring a different problem with it."

Such as...?

From the tests I've seen and read about online, the effects of this filter are negligible compared to the dichroic filter.

EDIT:

Bob, I'm not challenging you, I just asking, seriously. I've read all of Art Adams' articles on this issue. Do I undertand the physics? Not entirely, but I'm not totally ignorate of them, either.

The bottom line is I'm a "results" kind of person. The physics really doesn't impact my decisions that much. However, "results" do.

I took Art's before and after images, put them in Vegas, tweaked them, and got what appears to me to be a match; no green tint, no loss of red vibrance. By carefully adjusting the color balance and saturation, I like what my eye perceives as the results of the new Tiffen T1 filter. That's all I can really go on, when it's all said and done.

farss wrote on 10/16/2009, 6:43 PM

I'm not challenging you either :)

I'm an engineer, in my world there is no "perfect", just best fit for the purpose.

To answer your question. Well I don't have a concrete answer. Any filter has to have some impact. How much and what it impacts is the question and I don't know the answer to that at this stage. I'd like to see some hard numbers or graphs. I'm going to buy one of these filters and see if I can get it analysed, then we'll have some hard core information to make informed decisions.

On the other hand if what you're seeing floats your boat then go for it. You've found your best fit solution, not like this filter costs that much anyway.

Sony made a design decision with this camera. I seem to be one of the few that think it was a good one. Now that Tiffen have this filter we can mitigate the downside of that decision. I prefer having choices but I do like to see hard science to help me make those decisions, I don't entirely trust my eyes.

Bob.

Jay Gladwell wrote on 10/16/2009, 7:41 PM

"Sony made a design decision with this camera. I seem to be one of the few that think it was a good one."

We're in agreement, then. Adn yes, several people online have nitpicked at the camera and Sony for the decision.

Again, I have to rely on the results. Show me another camera that delivers equally beautiful images for the same money.

No, there is no "perfect." But am awfully pleased with this camera, even without the new filter. I'm thinking that the T1 will only make a good thing better.

Tomorrow's shoot will tell, for me, anyway.

Andy_L wrote on 10/17/2009, 7:59 AM

please forgive my extreme ignorance on this subject, but is this red-shift in the blacks something that can be easily corrected using, for example, Vegas' color correction filter (instead of a physical filter over the lens)? Or does that introduce unwanted shifts into other unaffected tones?

Jay Gladwell wrote on 10/17/2009, 8:06 AM

No, unfortunately, it cannot. It goes further than that. When you correct for the far-red it throws everything else out of kilter.

You can read more about it here and here.

Jay Gladwell wrote on 10/19/2009, 12:07 PM

Unfortunately, I was not able to use the new T1 filter on Saturday night's shoot. Someone at AbelCineTech screwed and sent it regular FedEx overnight instad of priority with Saturday delivery. They did refund the cost of shipping.

The filter did arrive today (Monday). I did a few tests with various black materials I could find around the house. To make a long story short, it worked as promised. The blacks came out rich and black, no reddish/brown tint and no green vignette.

There is a half stop loss in light, but that borders on negligible. As was discussed above, there is some very minor tweaking in post to boost the red's saturation to their previous levels before adding the T1.

IMHO, this filter helps make a great camera even better. I'm a happy camper!

farss wrote on 10/19/2009, 3:32 PM

I just posted some very crude test results at DVInfo:

http://www.dvinfo.net/forum/1434814-post24.html

As I said this is an extremely crude test as I don't have this filter as yet.
Make of it what you will.

Bob.

Jay Gladwell wrote on 10/19/2009, 4:37 PM

Certainly the filter has an effect, there's no debate about that.

I took the two bitmaps and dropped them into the timeline. Using the vectorscope, the waveform monitor, my eyes, and a few minutes I came upon with the following:

For the kind of work I do, and for the money I'm getting, this is close enough. If they want it better, they can spring for a session on Da Vinci. ;o)

Can't seem to get the images sized right to get rid of the jaggies.