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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Raven black hole sun issue

J

Justin Litton

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This conversation already started on the "RED RAVEN Camera Group" on Facebook, but I thought I would bring it over to the reduser forums since there are fewer mouth-breathers here and I thought someone at RED might be interested. :-P

I owned a BMD URSA 4K for 1.5 years and shot with it almost exclusively so I know very well what the "black hole sun" looks like. I received my new Raven recently and I LOVE it. It's easily the best camera I've ever owned and it's already changing my life. That being said, I did discover a small black hole sun issue when I did some initial test shooting at sunset on the second night I had it. Funnily, I didn't make any comments here about it or even keep the footage because I am so familiar with the issue that my only thought at the moment was something along the lines of "Hmm. I'm surprised to see that on the Dragon sensor, but oh well. It's much better than what I'm used to and I've become good at fixing it in post." Haha.

So... today on the FB group, there was some lovely 120fps test footage posted. This is the clip:
https://www.youtube.com/watch?v=n_Rk2K2oAtI

In the very opening shot, if you look at the sun, you'll notice a somewhat inconsistent looking purple ring. Then, at 0:38 with the shot over the water, there's a purple ring again and in fact the ring is doubled because the sun is reflecting off the water. I've seen this purple ring before and it's one of the ways that black hold sun manifests itself. I know it can look strange, but others on the group were pointing out that they felt it was purple fringing from the lens. I'm almost positive it isn't that. I've seen purple fringing before, and this just doesn't look the same.

So what do we think? Do all the Ravens have this artifact or just a few? Do the larger cuts of the Dragon sensor also do this?

Again, for clarity, I'm not even bothered by this all that much but I do find it interesting and I'd think RED might be able to fix it in a firmware update. I've also seen this effect in BMD and Sony cameras and even in Alexa footage! My understanding is that no camera is completely immune to this issue.
 
Also, if an R3D frame needs to be uploaded to clarify this, then I'm pretty confident I can go out and reproduce this pretty much any time if needed.
 
On the same note, how do you fix purple fringing? I've combed the forums for all posts about purple fringing, and though everyone is quick to tell you that it's a common artifact that affects every camera in the world (even though I've only ever seen it personally on Dragon footage--and several times at that); I still haven't seen a concise summary of how to get rid of it. I would like to know, since I'll be getting a Raven this year (I can hope).
 
I had a discussion with Justin on the FB forum, I have yet to encounter this issue and had a shoot last week that had me shooting into the sun quite frequently. I had no purple ring around the sun, odd fringing, whatever you want to call it. Shot on Zeiss and Canon glass.

I used to encounter it a lot on my FS700, not with the sun, but with edges in and around high contrast areas. None on my Raven.
 
i shot straight into the sun many times so far and never got a black hole either, i have got the purple fringing around flash lights in a night scene but it was because of my lenses CA when wide open, id close it down a half stop and it would disappear.
 
No issues here as well and I just shot into the sun last night and a few minutes ago.
 
If this is the case I imagine on extremely punchy sources that are insanely overexposed, like clear sky sun reflections and perhaps something like a plasma torch, where this could exist.

Likely fixable via firmware/color science update. Maybe not.

RED would likely need to look at an R3D for sure.
 
Never had this happen in any of the REDs I have ever owned. But it is fairly overexposed. Specially the 2nd shot. Was this shot with deep ND and wide open or no ND?
 
Daniel Stilling said:
Never had this happen in any of the REDs I have ever owned. But it is fairly overexposed. Specially the 2nd shot. Was this shot with deep ND and wide open or no ND?
Click to expand...

Same here, and I shoot into the sun all the time....
8.jpg


Have you tried changing the color to DragonColor instead of Dragoncolor2. Try that and see if it helps...
 
Don't over-expose, try changing the color settings and see if it disappears.
 
I'm my experience with the black hole issue on BM cameras. It's a sensor problem and not fixable in a firmware update. However, red seems to care about their customers much more than BM. So if it is an issue, red will take care of it.
As for a fix in post. In the most recent resolve release there is a "black hole fix" I recall seeing in one of the menus. Haven't tried it though.
 
It's a bit freaky that it is in the reflection. It shouldn't be "as" intense in the reflection. Wonder if it is that glass.

David
 
Someone on the FB forum confirmed that it is the Canon 50mm, not the Raven.
 
"Confirmed" isn't exactly the word I'd use. He just said it was the lens and he's wrong because I'm not talking about purple lens fringing. This is about the black hole sun issue that is manifesting itself as a purple ring around the sun. I understand that they are both purple but really they don't look exactly the same. I have seen this effect myself on my Raven using two different lenses. Neither were Canon glass.
 
Justin Litton said:
"Confirmed" isn't exactly the word I'd use. He just said it was the lens and he's wrong because I'm not talking about purple lens fringing. This is about the black hole sun issue that is manifesting itself as a purple ring around the sun. I understand that they are both purple but really they don't look exactly the same. I have seen this effect myself on my Raven using two different lenses. Neither were Canon glass.
Click to expand...



True, but either way this seems more isolated than a common occurrence, I've never encountered it on any of the Reds I've worked with. Definitely get ahold of someone at Red, if it's a bug then I hope it's resolved soon for you as well as the gent who made the original video.
 
Strange, i have never seen this in any R3D files. I have seen purple fringing but not this.
 
I had this happen on my Weapon shooting at an exposed light bulb. All I needed to do was ajust the white balance and voila it was gone.
 
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