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Consequence of Using IRND Filters on Helium?

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Andy Maser

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How bad of an idea is it to use some of the IRND filters I still have laying around with the Helium sensor? Do I need to buy new filters immediately? Will my colorist and client curse me? I use the Motion Mount most of the time (hence why I haven't updated my filters), but I'm heading into a project where it may make sense to roll sans Motion Mount and use external NDs.


Thanks!
 
It'll really mess with your green/magenta tint, especially at higher strengths.

However, if you are shooting RAW it is a trivial fix so it shouldn't matter too much.

But yes, at some point, you should get new ND's.
 
Andy Maser said:
How bad of an idea is it to use some of the IRND filters I still have laying around with the Helium sensor? Do I need to buy new filters immediately? Will my colorist and client curse me?
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It's not that big a deal, but shoot a color chart if possible at the beginning of each setup or each location if possible.
 
Why would IRND filters have any negative impact? As I understand the Dragon and I am assuming the Helium sensor are insensitive to IR. If this is the case a filter that does not pass IR should not have any impact on a sensor that doesn't respond to IR? The assumption that Helium is IR insensitive is just that and I have done no testing nor seen any testing to confirm or deny. I will be very interested if somebody knows a resource on this subject?
 
Tom Gleeson said:
Why would IRND filters have any negative impact?
Click to expand...

Typically, IRND filters like the Schneider Platinums and Tiffen IRNDs have a green tint to counteract infrared light tinting shadows magenta. The stronger the ND, the stronger the tint. When using IRND filters on cameras insensitive to IR pollution and before white balancing, your images would just be green.
 
Satsuki Murashige said:
Typically, IRND filters like the Schneider Platinums and Tiffen IRNDs have a green tint to counteract infrared light tinting shadows magenta. The stronger the ND, the stronger the tint. When using IRND filters on cameras insensitive to IR pollution and before white balancing, your images would just be green.
Click to expand...


Thats interesting. I bought a set of Schneider Platinums when they first came out and promptly returned them after the first shoot as the heavy filters did very odd things to the image. They have probably sorted this out by now. I hope I don't have to go back to IRND with the Helium.
 
Marcus Friedlander said:
It'll really mess with your green/magenta tint, especially at higher strengths.

However, if you are shooting RAW it is a trivial fix so it shouldn't matter too much.

But yes, at some point, you should get new ND's.
Click to expand...


Thanks for that!
 
Satsuki Murashige said:
Typically, IRND filters like the Schneider Platinums and Tiffen IRNDs have a green tint to counteract infrared light tinting shadows magenta. The stronger the ND, the stronger the tint. When using IRND filters on cameras insensitive to IR pollution and before white balancing, your images would just be green.
Click to expand...

Correct. We have a set of Firecrest IRND's, and shot with them in blazing California sun (in the mountains where weird things happen anyway), and we def got color issues. Even though RED shoots RAW, if your color's are boned in camera, that's information you can't get back. You can fix in a final grade, but in a dailies grade can be difficult as you have less control.

Once we flipped to Motion Mount, all our problems went away. Also white balancing and having a color chart help massively too.
 
Nick Morrison said:
Correct. We have a set of Firecrest IRND's, and shot with them in blazing California sun (in the mountains where weird things happen anyway), and we def got color issues. Even though RED shoots RAW, if your color's are boned in camera, that's information you can't get back. You can fix in a final grade, but in a dailies grade can be difficult as you have less control.

Once we flipped to Motion Mount, all our problems went away. Also white balancing and having a color chart help massively too.
Click to expand...

Hey Nick, I was lead to believe by Phil Holland's tests that the Firecrest ND filters were color neutral. What kind of color shifts were you seeing with your footage? I was literally just about to order some from B&H and then I saw your post.

Re: OP. I just sold my set of Tiffen IRND filters because they caused serious green shift with the Helium image.
 
Tom Gleeson said:
I bought a set of Schneider Platinums when they first came out and promptly returned them after the first shoot as the heavy filters did very odd things to the image.
Click to expand...

The Platinums are absorptive and were intended to be used with cameras like the Alexa and Sonys and in conjunction with camera white balancing. They never worked well with the Red MX sensor, instead you had to use hot mirror or dichroic filters which are reflective to eliminate IR pollution. The Dragon sensor (and possibly a function of the revised OLPF?) was less sensitive to IR, so you could use normal NDs. You can also use rare earth element ND filters like Mitomo True NDs which work great on both types of sensors.
 
Formatt Firecrests and Nisi filters are also supposed to be rare earth element filters like the True NDs, so I'm curious why there have been so many reports of color shifts with the Firecrests. I have not yet tried either of these two brands, but they are both quite a bit cheaper than the Mitomos, which are around $600 USD per 4x5.65 filter and have a delicate surface coating. Maybe they have stricter quality control?
 
Ok, I lost track of the latest thread about nds so I awake this.

Should you use irnd filters with helium or not? I need a few nds to a new lens and im not sure I will go with irnd anymore.
 
If you use IRND filters' your image will be tinted green. However, shooting raw means you can rebalance your image fairly easily. But you will most likely need to shoot a color chart.

But you SHOULD still be using regular ND's and NOT IRND's.
 
Is this the same for the Scarlet-W Dragon?

Marcus Friedlander said:
If you use IRND filters' your image will be tinted green. However, shooting raw means you can rebalance your image fairly easily. But you will most likely need to shoot a color chart.

But you SHOULD still be using regular ND's and NOT IRND's.
Click to expand...
 
I tested my new Firecrest filters today for first time. I did a simple test against a neutral background comparing them to a clean lens (no filtration)
1. When I bought these i discovered that they weren't all the same my .9 and 1.2 where labeled Firecrest Ultra IRND. The 1.5 and 1.8 where simply labeled as Firecrest ND (no Ultra or IR designation)
2. In the test the IRND Ultra filters showed almost no color shift at all.
3. The regular Firecrest NDs showed a bit of shift, although very correctable. The 1.5 was "cooler" or had a bit of a blue to it and a bit of Magenta, to elaborate in RedCine X I had to take the color temp from 5600 to 6200 and the tint to 2.98 to make it match the unfilterted shot. The 1.8 didn't seem to have any magenta but it to needed the temp raised to 6200 kelvin to match the original unfiltered clip. I found it odd that the shift was more blue and not either green or magenta. Again the shift was minimal and easily fixed. The interesting this with the Firecrests is that it was the IRNDs Ultras that looked nearly perfect, not the non IR versions.

Edit: this test was done on a Helium camera.
 
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