Blackmagic Forum

I'm currently editing a multi camera shoot of a benefit gala where I did the wide shot on the UM46k with the Tokina Cine 50-135mm T3. Because of the 114mm thread I had no IR filter available and the preview looked good. Now in the edit suite I have some scenes with singers in black clothes getting magenta - IR pollution biting me back.

So I was looking for some non-ND clear IR cut filters in 4x5.65 sizes and found the Schneider True-Cut IR Camera Filter Kit with its 3 filters: 680nm, 715nm and 750nm.

I'd like to avoid buying the whole set as probably just one of the three is the right one for the UM46k.
My educated guess is the 680nm because it is close to the visible light and the description says it helps to prevent IR spill with black cloths for cameras like the Sony EX1.

Any other comments, suggestions, experiences?

BTW: I have already a set of Schneider Platinum IRND 0.6/1.2/1.8.

Robert Niessner wrote:I'm currently editing a multi camera shoot of a benefit gala where I did the wide shot on the UM46k with the Tokina Cine 50-135mm T3. Because of the 114mm thread I had no IR filter available and the preview looked good. Now in the edit suite I have some scenes with singers in black clothes getting magenta - IR pollution biting me back.

So I was looking for some non-ND clear IR cut filters in 4x5.65 sizes and found the Schneider True-Cut IR Camera Filter Kit with its 3 filters: 680nm, 715nm and 750nm.

I'd like to avoid buying the whole set as probably just one of the three is the right one for the UM46k.
My educated guess is the 680nm because it is close to the visible light and the description says it helps to prevent IR spill with black cloths for cameras like the Sony EX1.

Any other comments, suggestions, experiences?

BTW: I have already a set of Schneider Platinum IRND 0.6/1.2/1.8.

I know some have had good success with the 680 IR cut on BMD cameras.

I also have found the Schenider PLatinum IRND's to be not very good at all ! IS that why you're adding an IR clear to the front ?

JB

John Brawley wrote:I know some have had good success with the 680 IR cut on BMD cameras.

Thanks John.

John Brawley wrote:I also have found the Schenider PLatinum IRND's to be not very good at all ! IS that why you're adding an IR clear to the front ?

No, the clear IR is meant for indoors when I want to film a stage with tungsten lights.
Interesting that you were not happy with the Platinum IRNDs because I had always nice results.
But I am planing to buy one of their new Schneider RHOdium FSND 2.4 filter which are said to be brilliant and super neutral along the full spectrum.

Robert Niessner wrote:Interesting that you were not happy with the Platinum IRNDs because I had always nice results.
But I am planing to buy one of their new Schneider RHOdium FSND 2.4 filter which are said to be brilliant and super neutral along the full spectrum.

I found the Schneider Platinum to be very in-consistent at deeper numbers the 1.5, 1.8 and 2.1 (not in IR cut per-se)

They seem to be all over the place, big differences in both colour cast and exposure set to set.

JB

The new RHOdiums are said to be very consistent, Phil Holland did a quick test lately.
https://www.schneideroptics.com/ecommer ... x?CID=2238
http://www.reduser.net/forum/showthread ... ND-Filters

Robert Niessner wrote:The new RHOdiums are said to be very consistent, Phil Holland did a quick test lately.
https://www.schneideroptics.com/ecommer ... x?CID=2238
http://www.reduser.net/forum/showthread ... ND-Filters

I'm sure they are

Bit late to party though, after years of being poor performing. And not to mention many other options, like Lee, NISI, firecrest and Mitomo.

JB

To JB: On the topic of clear IR filters, do you ever use one when you shoot Ursa Mini 4.6K and Ursa Mini Pro?
If so, is it all the time or only in certain situations?

I tend to leave a Hoya IR cut filter on my Ursa Mini 4.6K at all times just to eliminate the possibility of pollution. I haven't run into any visible problems doing that, but I'm curious to know if that's a mistake and I just haven't been bitten by it yet.

Robert, I have the Schneider True-Cut 715 IR Cut 4x4". It works well combined with the Fujinon B4 Zoom . Used it on the wedding shoot yesterday and no problems.

But tests I've published using the SLR Magic APO primes demonstrated that my Schneider B+W 486 MRC gave superior results. If you only buy one, get the 680nm filter. If you are planning on shooting with very wide lenses, the 715 may be adequate as an alternate filter choice.


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Thanks Paul. I have several Heliopans myself and after looking into their specification curve I can see that it seems to cut off at 680nm too. I too could not find any adapter rings for 112mm.

Rick, I am curious: Why should the 715 be more adequate for very wide lenses? Did you have problems with the 680 in combination with very wide lenses?

Robert, the 680nm IR Cut Filters using surface coatings (rather than absorptive resins in the glass) are cutting infrared adequately at any focal length lens, so that you can't go wrong there on BMD sensors.

However the caveat is that very wide lenses may actually cut into the visible deep red spectrum which ran subtly affect the richness of skin tones. The multi-coated IR Cut filters are recommended up to 60 degrees angle of incidence so very wide lenses may not perform in the same way they work on wide to telephoto lenses.

I bought the 715 to handle the Fujinon 7.8mm Zoom and may also use it on the 18mm SLR Magic APO lenses when it's released. But if 18mm is as wide as the APO will go, I'll be looking for a new wider prime either 14 or 16mm TBD.

715 is not a good solution in general for the 4.6K sensor, the 680 or possibly a 700nm filter are best. But for the very wide lenses, 715 might provide the best results. Sorry I can't demonstrate that as my widest prime is 25mm APO.

In light of this discussion, I've been looking at Saturday's wedding video shot only with the 715 filter. My most used focal length on the Fujinon was 7.8mm due to the close quarters in the interior shots, but I also used it for wide daylight exteriors. Thankfully all looks good so far even when I was shooting above 20mm.

The front element on the Fujinon is 95mm across. The 4x4" filter covers at 7.8-156mm... barely. You're smart going with 4x5.6" filters. My NiSi IRND set is 4x5.6" and they're easier to work with.


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Rick, has anyone posted any empirical testing that clearly shows that the level of IR cut makes a visible difference on very wide lenses?

I've run with the Hoya IR cut (which rolls off IR at around 680) on the 4.6K even with a tokina 11-16 on the 4.6K Ursa Mini and to my eye it performs the same as all my other focal length lenses. However, I would hate to learn the hard way that it isn't always the case.

Jamie LeJeune wrote:To JB: On the topic of clear IR filters, do you ever use one when you shoot Ursa Mini 4.6K and Ursa Mini Pro?
If so, is it all the time or only in certain situations?

I tend to leave a Hoya IR cut filter on my Ursa Mini 4.6K at all times just to eliminate the possibility of pollution. I haven't run into any visible problems doing that, but I'm curious to know if that's a mistake and I just haven't been bitten by it yet.

Hi Jamie.

No I have never run a CLEAR IR, only when using ND's and I also use IRND's, not separate IR or ND filters.

I will say that there is a tendency to have the Ursa's all be more red in the blacks generally, but i've always attributed this to the "look"

JB

Jamie, I know of no one testing very wide lenses with 680 versus 715nm filters on a subject including skin tones. I'll be sure to do it when I get a very wide lens. I have tested 680 and 715nm filters on wide, normal, and 'portrait' focal lengths and the 680nm performs better than the 715mm IR Cut although as I mentioned the 715nm does well enough on my Fujinon Zoom while I'm shooting 2K.


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John Brawley wrote:

Jamie LeJeune wrote:
Hi Jamie.

No I have never run a CLEAR IR, only when using ND's and I also use IRND's, not separate IR or ND filters.

I will say that there is a tendency to have the Ursa's all be more red in the blacks generally, but i've always attributed this to the "look"

JB

Thank you JB for the clear answers
Under tungsten lighting the 4.6K sensor really seems to pick up a hefty amount of IR on black cloth even when there's no ND used.
Have you gotten any push back from your colorist (or your art department) about that "look"?