Tiffen T1 IR cut filter for removing IR contamination with ND filters

[Shashin]

I have a B+W 4.0 ND filter and IR contamination is a problem with this and other filters. One of our members, Graham from OR, recommended using the new Tiffen ND filter line as it has an IR cut filtration built in. I really did not want to add more ND to an already dense filter and I did not want to buy two new Tiffen filters to get the ND of 4.0.

I did research on the new Tiffen IRND filters and found they had a slight green cast. During my search I came across the Tiffen T1 IR cut filter which also had a slight green appearance. This filter seems to be a favorite of videographers, especially for use with certain Sony cameras that have a strong near IR response. I figured the green cast in the Tiffen IRND filters was probably related to how this filter worked and I should be able to simply put it in front of my b+W. At about $78 dollars for a 77mm filter, it seemed worth a shot.

I did a quick and dirty test today. Here is the original scene. No processing and straight out of the camera:

Here is the exposure with only the B+W 110 4.0 ND filter straight from the camera:

Here is the B+W filter plus the Tiffen T1 IR cut filter straight from the camera:

Correcting the color in post can get the B+W filter closer. With just rocks and water, it is easier than water and trees, but is a simple processed image using white balance in ACR and a quick fix to contrast:

Here is the corrected shot that used the Tiffen T1 filter:

To me, the Tiffen T1 filter really helps IR contamination when using strong ND filtration, especially B+W filters. It is much easier to get natural color out of an image. It also seems to be an inexpensive solution. I believe the filters come not only in round, but also square.

 

[GrahamWelland]

Glad to see that you resolved your IR problem. Ultimately you only needed the IR to be cut by a single filter and the T1 does that without adding any additional ND filtration and retains the value of your B+W ND's which are great filters.

I went with all Tiffen IRND's because of the simplicity of not having to worry about combining filters. Ultimately though you only need one filter to be IR cut to get the result you've been looking for.

:thumbs:

 

[Shashin]

A bit of an update and a correction. In the example above, I am using a B+W 113 4.9ND filter--that is 13 stops.

After a little more experience with using it, the IR cut filter has a reduced effect with foliage when the sun is low, or in other words, when the object is highly reflective in IR and the IR component to the light is high. It still is easier to control the IR contamination with the T1 filter.

 

[Wayne Fox]

Good plan. Personally I purchased the Tiffen IRND filters instead of just the IR filter and sold my B+W filters because I often stack 2 or 3 ND filters and just didn't want to add another piece of glass and 2 surfaces to the stack. Never really tested it but I think even when I stack the 4 stop and 6 stop I get really good results, better color than ND without the IR absorption.

 

[Shashin]

Wayne, I did looking into replacing my 13-stop filter with Tiffen IRNDs, but it meant I would need three filters to get the density and so it seemed like a better solution to simply put an IR cut filter on the B+W.

 

[Wayne Fox]

wow, 13 stops! I agree, adding the IR cut on that is the way to go ...

Surprising any light gets through

 

[GrahamWelland]

Actually I also use 13 stops using the Tiffen IRNDs. You actually need two filters for this density - 1.8 & 2.1 together. I stack a 77mm and 82mm filter together to avoid vignetting.

For bright sunlight you'd be surprised how even with this amount of filtration there's still plenty of light coming through but you definitely aren't going to be seeing anything through the viewfinder! What you do start running in to is light leaks in the camera body, back-body interface, lens DOF scale and pretty much anywhere that it can sneak in.

For example:
DF & IQ160 - 2min f/16 ISO50

With the addition of gaffer tape around the body/back interface:

 

[Shashin]

I cap my viewfinder to stop light leaks, which not only causes streaks on the image (see the right side of my second example image above [that is light not only coming through the viewfinder, but also through the raised mirror), but also messes with the exposure system with a new 9-stop ND filter I purchased. I cannot meter with 13-stops ND, but I can meter very well with 9 stops.

The B+W 113 was design for photographing the sun along with the B+W 120 20-stop ND filter. I have a B+W 120, but have not had the time to test it, for obvious reasons as testing it takes a lot of time.