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  1. #1 Return of Purple Fringing. 
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    Hey ya’ll

    Anyone else experiencing more severe then usual Purple fringe with Komodo?

    I am expecting lots of call outs of this just being chromatic aberration, which may be a part of this but I have spent the past few days testing every combination of lenses I own (Not a ton) but cannot find a lens that won't produce neon purple fringing. Lenses that never produced this on other bodies.

    I was an original R1 owner, loved that camera dearly. During my time with that camera I experienced the documented Purple fringe issues with its sensor often. I shot with many lenses, and all in all it was inevitable that if you are shooting against a white sky, you will have severe purple artifacts.

    In the years since owning that camera, I have shot mostly with the Alexa and my own FS7 and occasionally rented Helium or a buddies old Scarlet W and I have never had the issue on my FD set, Canon L glass or CP2's (CP2's did it on the R1 but never Alexa).

    Could this be a lack of filtration on the sensor? What sort of filtration does the komodo have if any?
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  2. #2  
    Senior Member Bastien Tribalat's Avatar
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    Quote Originally Posted by Rick Cook View Post
    Hey ya’ll

    Anyone else experiencing more severe then usual Purple fringe with Komodo?

    I am expecting lots of call outs of this just being chromatic aberration, which may be a part of this but I have spent the past few days testing every combination of lenses I own (Not a ton) but cannot find a lens that won't produce neon purple fringing. Lenses that never produced this on other bodies.

    I was an original R1 owner, loved that camera dearly. During my time with that camera I experienced the documented Purple fringe issues with its sensor often. I shot with many lenses, and all in all it was inevitable that if you are shooting against a white sky, you will have severe purple artifacts.

    In the years since owning that camera, I have shot mostly with the Alexa and my own FS7 and occasionally rented Helium or a buddies old Scarlet W and I have never had the issue on my FD set, Canon L glass or CP2's (CP2's did it on the R1 but never Alexa).

    Could this be a lack of filtration on the sensor? What sort of filtration does the komodo have if any?
    Can you share some screenshots (or even better some R3D files) so that we can check this to help you ?
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  3. #3  
    Senior Member Christoffer Glans's Avatar
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    Have you shot something at T5.6 - T8.0? Most lenses create CA, even stopped down a little. The color science or sensor might exaggerate that spectrum and therefore you will see it more on Komodo, but in essence... it's a prime reason why good glass costs more.
    Maybe you could rent something like a Master Prime and see how it behaves.
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  4. #4  
    Senior Member Alex Lubensky's Avatar
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    Quote Originally Posted by Rick Cook View Post
    Hey ya’ll

    Anyone else experiencing more severe then usual Purple fringe with Komodo?

    I am expecting lots of call outs of this just being chromatic aberration, which may be a part of this but I have spent the past few days testing every combination of lenses I own (Not a ton) but cannot find a lens that won't produce neon purple fringing. Lenses that never produced this on other bodies.

    I was an original R1 owner, loved that camera dearly. During my time with that camera I experienced the documented Purple fringe issues with its sensor often. I shot with many lenses, and all in all it was inevitable that if you are shooting against a white sky, you will have severe purple artifacts.

    In the years since owning that camera, I have shot mostly with the Alexa and my own FS7 and occasionally rented Helium or a buddies old Scarlet W and I have never had the issue on my FD set, Canon L glass or CP2's (CP2's did it on the R1 but never Alexa).

    Could this be a lack of filtration on the sensor? What sort of filtration does the komodo have if any?
    Each set of lenses that You've mentioned - has CA. Be it .CP2, FD of Canon L - all of them are known to have CA (some more, some less). They are not MP, or even UP - the more resolution you have the more of CA you'll see. While, starting from 5d mk II Canon had built-in CA corrections on the fly, I suppose something similar could be built in on some camera bodies. Thus, never seen nothing like this on Red bodies - Helium 8K, Dragon 6k, Gemini 5k, Scarlet MX - all show the same CA on my RPZ 18-85 T2.9 cine zoom.
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  5. #5  
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    I was expecting the responses I got since it’s the typical response when you search for issues related to purple fringing on red sensors here.
    Yes, the lenses I own have some level of CA, no they are not masterprimes. So is everything shot on a red body shot on masterprimes or at 5.6? As I’ve mentioned I shoot on a lot of different camera bodies and this is only a problem I’ve encountered on the the red bodies I’ve owned.
    It could be color science, it could be pixel density, it could be specific to OLPF, or lack of IR cut? Hell I posted because maybe it’s my Komodo in particular.

    I’m was more curious what others have done to avoid this on their sensors or if they experience it at all. I can certainly post some r3ds later.

    Thanks!
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  6. #6  
    Senior Member Alex Lubensky's Avatar
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    Quote Originally Posted by Rick Cook View Post
    Hey ya’ll

    Anyone else experiencing more severe then usual Purple fringe with Komodo?

    I am expecting lots of call outs of this just being chromatic aberration, which may be a part of this but I have spent the past few days testing every combination of lenses I own (Not a ton) but cannot find a lens that won't produce neon purple fringing. Lenses that never produced this on other bodies.

    I was an original R1 owner, loved that camera dearly. During my time with that camera I experienced the documented Purple fringe issues with its sensor often. I shot with many lenses, and all in all it was inevitable that if you are shooting against a white sky, you will have severe purple artifacts.

    In the years since owning that camera, I have shot mostly with the Alexa and my own FS7 and occasionally rented Helium or a buddies old Scarlet W and I have never had the issue on my FD set, Canon L glass or CP2's (CP2's did it on the R1 but never Alexa).

    Could this be a lack of filtration on the sensor? What sort of filtration does the komodo have if any?
    Each set of lenses that You've mentioned - has CA. Be it .CP2, FD of Canon L - all of them are known to have CA (some more, some less). They are not MP, or even UP - the more resolution you have the more of CA you'll see. While, starting from 5d mk II Canon had built-in CA corrections on the fly, I suppose something similar could be built in on some camera bodies. Thus, never seen nothing like this on Red bodies - Helium 8K, Dragon 6k, Gemini 5k, Scarlet MX - all show the same CA on my RPZ 18-85 T2.9 cine zoom.
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  7. #7  
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    I am not at home atm so can’t upload any raw clips. Here is some quick dirty footage shot with a FD 50 1.4 stopped down to F2. Again, this lens does have CA but it never glows purple like this on any other camera I have shot with ranging from DSLR’s up to MiniLF. Every lens I own is glowing like this. Maybe CA is creating out of gamut color causing it to light up like this?

    https://youtu.be/kbt9RunUtow
    Last edited by Rick Cook; 11-27-2020 at 09:08 AM.
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  8. #8  
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    That’s ugly. I seem to remember this on some other red cam but can’t remember which cam/firmware. I know Komodo leans magenta, so that could be part of it. If you don’t see it on other cams in the same scenario then that def tells you it’s the camera.
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  9. #9  
    Senior Member Christopher S Johnson's Avatar
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    Quote Originally Posted by Rick Cook View Post
    Wow, that is really bad. I'm interested in seeing the R3D and seeing what bringing down the sharpness does.
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  10. #10  
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    Could be wrong, but that seems almost too consistent to be CA; it seems equal across the entire frame. I can even see it while viewing on my phone (the smaller screen usually hides a lot of lens performance issues), and there's no way you wouldn't have noticed it on other cameras if it was happening there (especially Helium and Scarlet-W)...Conversely, maybe it is just exaggerated/visible because there's no off-sensor-stack OLPF in Komodo? Have you shot with any other 4k+ cameras that lack typical OLPF (like the BMDs)?

    Graeme had a purple de-fringing LUT specifically for this purpose, but I believe it was for Dragon and eventually was rolled into the colour science. Re-update the firmware, black shade (do you black shade with Komodo?) and try your least CA lenses to see if that fixes/helps it. Also might be worth sending off a log and .r3d still to RED and see if they have any thoughts.
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