Thread: Infrared Pollution Control on URSA Mini 4.6K sensor

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  1. #1 Infrared Pollution Control on URSA Mini 4.6K sensor 
    Senior Member rick.lang's Avatar
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    Didn’t want this issue to be buried in the various threads that discuss the 4.6K sensor. Just posted this to the official BMD forum:

    I have created a four part series from the tests i did 2017-03-04 to examine the control of infrared contamination on the URSA Mini 4.6K PL camera using a variety of filters.

    Parts 1 and 2 feature IRND filters. The question was raised about combining the Mini Pro filters with additional ND filters to see if the Mini Pro filters will suffice to control infrared. Part 2 may answer that question for you as I present the three scenarios.

    Part 1 examines just the 7 NiSi Nano IRND filters which behave in the same manner as the 3 built-in IRND filters found in the URSA Mini Pro cameras.


    https://vimeo.com/207484340

    Part 2 examines the use of the SLR Magic Image Enhancer, B+W 486 MRC IR Cut, and S:R Magic Vari-ND filters alone or in combination with the NiSi filters to approximate how those filters may perform with the built-in IRND filters on the URSA Mini Pro camera. I can’t be sure of course because i am not actually testing the Mini Pro.


    https://vimeo.com/207488176

    No password required.

    Please read the additional notes for each video. Hope you find these tests useful. I also have simply graded all these clips and the results indicate that all clips appear to be quite good matches once they are corrected in post. I may present the graded videos if you want to see those, when I can upload them, but next week I’ll upload Part 3 and Part 4 that are specific to the SLR Magic Image Enhancer and the SLR Magic Vari-ND.

    Edit:
    Here is the Part 3 that isolates the SLR Magic Vari-ND II filter so you can judge its efficacy. It is not intended to affect infrared light, but you may see some changes in colour at the maximum setting. It is easily corrected in post.


    https://vimeo.com/208398054



    Edit:
    Here is Part 4 with the NiSi Nano 1.8 first and then with the SLR Magic Image Enhancer added for a subtle improvement to infrared filtration. The SLR Magic Image Enhancer shapes visible light and near infrared and then cuts infrared beyond the ‘normal’ cutoff on most IR Cut filters. I also added a distortion test of the 85mm APO and it looks good as a closeup lens (focus was 9.5’).

    https://vimeo.com/208547087



    Edit:
    Reissued a new version of Part 4 which compares the Image Enhancer Pro with the NiSis Nano IRND. Using ACEScct 1.02 with BMD Film $,6K v3 IDT and Rec.709 oDT. I’ll use this combination in the future unless I post otherwise for all my 2K deliverables. If you can set your monitor to Rec.709 for proper viewing otherwise you won’t see the rich colour. This was both reframed and stabilized in post from 4.6K capture on a DCI-4K timeline and DCI-2K Deliverable. Finally something I like and looks presentable (I hope):

    https://vimeo.com/211031513

    Last edited by rick.lang; 04-01-2017 at 06:54 AM.
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  2. #2  
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    Quote Originally Posted by rick.lang View Post
    Didnít want this issue to be buried in the various threads that discuss the 4.6K sensor. Just posted this to the official BMD forum:

    I have created a four part series from the tests i did 2017-03-04 to examine the control of infrared contamination on the URSA Mini 4.6K PL camera using a variety of filters.

    Parts 1 and 2 feature IRND filters. The question was raised about combining the Mini Pro filters with additional ND filters to see if the Mini Pro filters will suffice to control infrared. Part 2 may answer that question for you as I present the three scenarios.

    Part 1 examines just the 7 NiSi Nano IRND filters which behave in the same manner as the 3 built-in IRND filters found in the URSA Mini Pro cameras.


    https://vimeo.com/207484340

    Part 2 examines the use of the SLR Magic Image Enhancer, B+W 486 MRC IR Cut, and S:R Magic Vari-ND filters alone or in combination with the NiSi filters to approximate how those filters may perform with the built-in IRND filters on the URSA Mini Pro camera. I canít be sure of course because i am not actually testing the Mini Pro.


    https://vimeo.com/207488176

    No password required.

    Please read the additional notes for each video. Hope you find these tests useful. I also have simply graded all these clips and the results indicate that all clips appear to be quite good matches once they are corrected in post. I may present the graded videos if you want to see those, when I can upload them, but next week Iíll upload Part 3 and Part 4 that are specific to the SLR Magic Image Enhancer and the SLR Magic Vari-ND.

    Rick,

    At 1.8, I'm starting to see a green tint in the Nano NISI IRND filter. Am I seeing correctly or my eyes are going bad on me?
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  3. #3  
    Senior Member rick.lang's Avatar
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    There does seem to be a slight difference between IRND 1.8 and the rest, but until I test in an interior controlled shoot, I'm not positive. There were always changes in the quality of the sun, but I never took another AWB after I started shooting, yet I can see it was changing. I left it at 6000K and -15 tint. I'll check my Resolve settings, but I think I left Resolve at Camera Settings for the raw tab.

    When I post the colour-corrected stream, you'll see how similar most of the clips are to each other. Even then there are some variations when you focus on the white card leaning on the log beside Tatum.

    I like having the extra strength at IRND 2.1 so that will be my go-to filter on sunny days.
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  4. #4  
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    Quote Originally Posted by rick.lang View Post
    There does seem to be a slight difference between IRND 1.8 and the rest, but until I test in an interior controlled shoot, I'm not positive. There were always changes in the quality of the sun, but I never took another AWB after I started shooting, yet I can see it was changing. I left it at 6000K and -15 tint. I'll check my Resolve settings, but I think I left Resolve at Camera Settings for the raw tab.

    When I post the colour-corrected stream, you'll see how similar most of the clips are to each other. Even then there are some variations when you focus on the white card leaning on the log beside Tatum.

    I like having the extra strength at IRND 2.1 so that will be my go-to filter on sunny days.
    That can be easily fixed in post. For the price of these filters compared to the others, they're a winner in my eyes. NISI it is. Thanks Rick!
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  5. #5  
    What are your thoughts on the Slrmagic Pro IE Filter? It seems like it's adding an unnecessary shift. I like the images without it a lot better. I know you can correct this stuff, but I'm just trying to figure out the use of that filter. I gotta look at it some more. It's half and half at the moment. I'd probably invest in irnds or ir cut with straight nds. I'd leave the variable for the quick stuff.
    Last edited by The HRHM; 03-08-2017 at 08:59 PM.
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  6. #6  
    Senior Member rick.lang's Avatar
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    Quote Originally Posted by Bino View Post
    That can be easily fixed in post. For the price of these filters compared to the others, they're a winner in my eyes. NISI it is. Thanks Rick!
    I passed your observation on to NiSi this evening. They'll be reviewing the tests shortly. I need to do a controlled test to see if there is a difference. I think I mentioned, when I lightly grade the clips, the results are very pleasing. Even the yellow cast on the Vari-ND at ND 1.8 comes up looking fine.
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  7. #7  
    Senior Member rick.lang's Avatar
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    Quote Originally Posted by The HRHM View Post
    What are your thoughts on the Slrmagic Pro IE Filter? It seems like it's adding an unnecessary shift. I like the images without it a lot better. I know you can correct this stuff, but I'm just trying to figure out the use of that filter. I gotta look at it some more. It's half and half at the moment. I'd probably invest in irnds or ir cut with straight nds. I'd leave the variable for the quick stuff.
    Different folks on the forum have a few favourite Vari-ND filters. The SLR Magic Vari-ND II includes an ability to set the degree of polarization and then set the ND strength. It's easy to use with a small handle to dial in your ND.

    The Image Enhancer Pro takes some getting used to. You may judge it better next week when I include some shots with the 85mm APO prime so Tatum's face is more prominent in the frame than the 25mm shots posted today. It's been designed to smooth out the spectrum reducing the spikes in some wavelengths trying to emulate the spectral response of tungsten without all that infrared radiation. I've posted other tests using other lenses but I was looking forward to seeing how it handled infrared on the 25mm and I think the tests indicate it did well. I'm going to be doing more tests with Tatum so the IE Pro will likely be on the camera regardless of the lens I use. In Part 4 coming next week, you'll see how it gives a different rendition of her face. These are subtle changes, like a good diffusion filtervthat you don't realize is there, but you like the results. That doesn't mean everyone wants that look of course and some folks prefer the cleaner image. It's not expensive to add to your kit. Use it several times and if it doesn't grow on you, then it wasn't right for you.
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  8. #8  
    Quote Originally Posted by rick.lang View Post
    Different folks on the forum have a few favourite Vari-ND filters. The SLR Magic Vari-ND II includes an ability to set the degree of polarization and then set the ND strength. It's easy to use with a small handle to dial in your ND.

    The Image Enhancer Pro takes some getting used to. You may judge it better next week when I include some shots with the 85mm APO prime so Tatum's face is more prominent in the frame than the 25mm shots posted today. It's been designed to smooth out the spectrum reducing the spikes in some wavelengths trying to emulate the spectral response of tungsten without all that infrared radiation. I've posted other tests using other lenses but I was looking forward to seeing how it handled infrared on the 25mm and I think the tests indicate it did well. I'm going to be doing more tests with Tatum so the IE Pro will likely be on the camera regardless of the lens I use. In Part 4 coming next week, you'll see how it gives a different rendition of her face. These are subtle changes, like a good diffusion filtervthat you don't realize is there, but you like the results. That doesn't mean everyone wants that look of course and some folks prefer the cleaner image. It's not expensive to add to your kit. Use it several times and if it doesn't grow on you, then it wasn't right for you.
    Yeah, I own the SLR Vari ND. I just haven't seen the Image Enhancer demostrated in a real world scene. I'll look out for your future tests. I just want more images before I set a verdict. Hopefully, we'll see how the NDs on the Ursa Pro performs. I wouldn't mind adding a quality 1 stop nd to that setup or even fill out the gaps the ursa doesn't provide. I still haven't took the BM plunge, but the Pro might be my first jab at it.
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  9. #9  
    Senior Member rick.lang's Avatar
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    Nice first BMD camera. Okay, I'll try to include more samples of the Image Enhancer Pro I'm using. This might also be doing double duty as it controls infrared better than I thought on the 25mm, but I suspected it might. Need to include when I do my APO comparisons as well to see if lens focal length affects the IE Pro.
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  10. #10  
    Senior Member rick.lang's Avatar
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    I updated the first post in this thread to include Part 3 of my recent tests.
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