Blackmagic Forum

Hi fellas...

I am looking to solve out how can I clean up the IR pollution that could disturb while using heavier NDs. I have regular Tiffen WW ND filters from 0.3 to 1.2. I didn't buy heavier than these because I know I could stack them. But as you know especially when using any ND heavier than 0.9, it is better if they are IRND.

In my case, I searched on forum and whole web but I couldn't find any comparison between Tiffen IRNDs and a combination of Tiffen T1+Regular Tiffen NDs. I am planning to buy a Tiffen T1 to cut IR pollution since I have a set of regular Tiffen NDs but it would be good to see how they are working together.

If you have any thought about it please share with me..

Thanks a lot.

Probably not very useful but I bought a set of Tiffen ND filters (a kit comprising of 0.6, 0.9 and 1.2) as well as ND Fader filters. I use them with the Tiffen T1. The T1 causes a slight shift in the green/magenta tint (pushes it more towards green). Without the T1, even for ND 1.2 the contamination is quite noticeable. Combined ND+IR filters, when stacked, may cause the colour to be worse with minimal additional IR removal (they'll also be more expensive). I think a plain IR-cut filter with normal NDs is a more versatile combination than a combined filter.

muratcangokce wrote:Hi fellas...

I am looking to solve out how can I clean up the IR pollution that could disturb while using heavier NDs. I have regular Tiffen WW ND filters from 0.3 to 1.2. I didn't buy heavier than these because I know I could stack them. But as you know especially when using any ND heavier than 0.9, it is better if they are IRND.

In my case, I searched on forum and whole web but I couldn't find any comparison between Tiffen IRNDs and a combination of Tiffen T1+Regular Tiffen NDs. I am planning to buy a Tiffen T1 to cut IR pollution since I have a set of regular Tiffen NDs but it would be good to see how they are working together.

If you have any thought about it please share with me..

Thanks a lot.

You will take a hit in resolution by stacking an IR + ND vs an IRND (noticeable on long lenses) and without an AR tray in something like a Panavision mattebox, you increase the chance of internal refections in the filters. Also, I believe that any dichroic filters shouldn't have any other filters in front as you can get some weird IR refections.

You also use up an extra tray in your mattebox. In the case of a 2 stage box w/ 138mm ring, I usually go for IRND so I can either play glass diffusion, a grad or stack a heavier ND if required in addition to the base ND1.2 or 1.5 and a 138mm pola. If you are working with a 3 or 4 stage production matte box, then that is less of an issue.

Finally, since you already have the set of NDs, adding a separate IR filter certainly is the best value but I would consider it unacceptable for rental. You could look at adding just an IRND 1.2 instead.

I'm facing the same issue. I want to shoot shallow so I drop as much ND in but I'm getting insane amounts of contamination. The other day I had a basic IR filter (can't remember what brand), ND 1.8 and ND .9 in bright sunlight and the subject's black pants were so incredibly contaminated they were a completely new color. I'm still searching for an IR filter that might filter out more IR than most standard filters. Can anyone help? I've seen tests, but many still allow IR contamination, and I'm looking for zero contamination. Is it possible?

You will take a hit in resolution by stacking an IR + ND vs an IRND

It's versatility/cost vs quality, but that said I haven't noted any resolution or general quality degradation as a result of using 2 or 3 filters stacked... maybe it'll be noticeable on the 4k camera.

Below is an example of a shot using stacked ND Filters and a T1 filter. I specifically chose a shot with a lot of plant matter in it (because green plants reflect a lot of IR and often look brown with IR contamination) (Canon IS 17-85mm f/4-f/5.6):
Example shot using ND1.2, ND0.3 and IR-cut/T1
Same as above but DNG file

And a shot with the same ND combination without the IR filter - shot shows severe IR contamination on both tree in background and black garments) (Canon IS f/2.8 17-55mm):
JPG with my idea of colour
DNG file

It would help if they were of the same scene... maybe I'll test tomorrow.