URSA Mini 4.6k The Original™ Magenta Cast Issue

I'm in for magenta.

I remember when someone on this forum was worried about magenta cast on early beta footage seen online. Everybody here tried to kill him..

Images shot like that are almost always (IME) going to produce problems - this does not pertain solely to BMD.
My 5DMKII/III would also haze up magentas on an image like that. You have stark roof reflection causing the magenta-ish color cast along with specular from the rail-guard shining right into the cam and the cherry on top is the mountain haze which by nature is blueish... The composition of this image was screaming Magenta even before the photographer hit the shutter button.

Anyway this is WHY we learn white balancing !!!! It took me 20 seconds to remove the cast - if one had the RAW file he could spend the next 20 minutes and make it look like beverly hills. Or call the mayor of that township and ask him to imprison the architect and planer who signed off on the roof color

The WB is based on the Sat-dish and the township facade-whites NOT the sky. This image-composition calls for dual WB-ing. Foreground and background.

That said, in dark scenes BM has issues with greenish darks and in bright scenes (other end of scale) with Magenta neutrals both are symptoms of the same cause - The Green channel or the Matrix representing it.
Any Cam. Matrix is going to be full of compromises at it strives to yield and overall good result. The rest if done by white balancing in post. Could BMD optimize the Metadata Matrix to fix it... IMO Yes. But such takes time and lots of feedback...

Before WB


Post WB

White balancing, no matter how derived, does not fix this problem. Your "fixed" example, while better overall, still shows a magenta cast on both sides and especially the right side. This is not a simple global magenta cast issue that can be fixed by any global adjustment. The exact reason as to WHY this is happening is pretty much irrelevant to the end user. What is relevant is that this issue has been shown to be a camera to camera hardware/manufacturing issue plain and simple which is borne out by user reports with clean cameras and plenty of clean samples to back it up. Bottom line: Anyone not happy with any amount of color cast in their camera doesn't have to put up with it. If people are happy with the results they can get by setting a white balance or any other post workaround on cameras that display this problem, that is their choice and I'm sure BM will be very happy too.

Hello everyone!
Sorry for misunderstanding but .... Am i right thats no matter why magenta is appearing there are units without ANY problems with ANY lenses and challenge only is get healthy unit ?

I am 99.99% sure the answer to your question is yes. The only challenge to the potential 4.6k buyer is getting a good one. Knowing WHY the issue exists does interest me, but only from an academic point of view. As a end user, I personally don't care if it's caused by the discord between a June Bug and a Barn Owl during a full moon. I don't like it and now know I don't have to accept it.

At issue is not a cast.

At issue is if there are corners that are a different colour.

Lenses can introduce this. We need to eliminate lenses.

You can shoot a wall without a lens in relatively low Light.

It just needs to be evenly lit.

JB.

It looks like the common problem one gets with adapting lenses not designed for the sensor in question. The a7S II and a7R II have this a lot.

The most common explanation I've seen of this is the rays at the corners hit the sensor at an oblique angle, hence causing the magenta shift. Quite common actually.

It would be nice to see the same tests with high end lenses on both the EF and PL mounts. If there's no color cast when the lens is taken off, the sensor is okay. It's a simple test.

I have my Um46 since 3 weeks and I have not magenta tint or magenta vignetting. Test in Prores, UHD and HD, 24,25 and 60fps with sigma 18-35, xeen 14mm, Canon 24-70, Canon 70-200. On outdoor natural light and indoor led and Tungsten light.

I have my Um46 since 3 weeks and I have not magenta tint or magenta vignetting. Test in Prores, UHD and HD, 24,25 and 60fps with sigma 18-35, xeen 14mm, Canon 24-70, Canon 70-200. On outdoor natural light and indoor led and Tungsten light.

This is great news Deyan Parouchev! Would you be able to post frames of a white paper taken with and without a lens? It is quite clear that the magenta issue is an isolated camera by camera problem. I certainly hope the majority of cameras are free from this problem. It frankly baffles me that people are still trying to figure out WHY it is happening and are coming up with possible solutions and workarounds when all they need to do is exchange their camera for one that doesn't have the problem! Maybe it's just human nature to try and heal the sick and injured?

Maybe it could be a light leak between the camera and the lens on some units ?

To OP

I downloaded your CinemaDNG Image and looked at it. What you have is a color cast.
This is perfectly normal. I was able to remove it simply by white balancing the wall - which btw. was very far from being evenly lit

You have been dealing with Color Casts all your life only NOT on a Green/Magenta Scale. But a on a Blue Yellow scale.
On most cameras if you shoot a White Wall like your's but set the White Balance setting in-camera @ 6500 Kelvin you are going to get a color cast. On most cams. this cast will sho up as too hot (Orange) or too cold (Blue). Reason is that there is a difference between Outdoor 6500 and Indoor 6500.

I don't know of ANY camera where one does not need to adjust the White Balance in Post. Most the time images are too warm and one needs to cool them down to make them look natural. The thing is, that a warmish image is MUCH more pleasing looking than a Magenta-ish image. And most people think of white balancing as in adjusting temperature(Yellow(Orange) - Blue) - and not so much tonality (Green/Magenta.

While 99% of all cameras I have been using tend to reveal an offset in the White Balance with too warm or to cold there are cameras (Like the Black Magic Design Camera) which in certain circumstances reveal this offset as Green/Magenta.

White Balance is not just adjusting colors on the warm-cold scale but just as equally adjusting balance on the green/magenta (tint) scale.

My Black Magic Mini URSA 4.6k does BUT ONLY UNDER CERTAIN CIRCUMSTANCES suffer from the newly coined "Magenta" issue. This is perfectly normal IMO as I would expect in 100% of all cases to have to deal with a color cast when grading ANY image. Whether the cast is yellow, blue, green or magenta - doesn't matter. It is a color cast, just the same.

If the URSA Mini 4.6K has a Magenta Issue then all other cameras have an Orange Issue. You just don't see people go around posting about latter as it is somewhat expected and accepted as being a White Balancing Issue. Green/Magenta is NOT generally accepted as a White Balancing Issue and thus frowned upon as a camera Malfunctioning where in fact it is the exact same problem as with red and blue only the color is another.

This issue in in my opinion nothing but a relatively simple White Balance Offset - only diff. is that the symptom's color is magenta instead of yellow.

I may be wrong and in the end I'll be taught differently and realize that every 3rd cam has a production error (Mine Included) - but I seriously doubt it. I have only had mine since Friday and only shot sporadically in-house for fun - and about 50% of them had a clear visual white balance offset in the direction of Magenta which I was able to fix just as easily as and offset in the direction of Orange. And while I find the Orange offset much more pleasing to look at doesn't make it less an offset than that of Magenta.

If enough of you send image to BMD and complain about the color cast being magenta instead of Orange - perhaps they'll alter the Meta Data (stored in each image) Matrix a little so that every color cast display as pleasing orange instead of ugly Magenta.

That said, every new camera (Especially the Matrix used to describe its colors) needs to be tweaked a little here and there over the course of time. And if you make a screen shot of the Matrix inside of the Meta Data from an April 2016 CinemaDNG file and compare THAT to a 2017 Meta Screenshot, chances are that the Matrix is not going to be identical. Perfectly normal.

And remember the greater the dynamic range and resolution of your camera the more revealing the artifacts of your lens. If any. Your lens is def. an uneven match for the URSA 4.6k. The fall-off to the sides is massive and you can achieve much better results with a slightly better lens.

PS - A certain scenario in which the issue is 100% repro...

0) Open Lens to Max Aperture and throw it out of focus when executing step 1.
1) In overcast (Diffuse Daylight) set WB in-cam to 5600 and acquire an Image of a 'White Wall' hit by the outside light with NO peripheral lighting going on.

This should reveal a magenta-ish color cast when viewed in an sRGB environment

I think we are getting confused between a color CAST, which is an even color tint - even across the frame, and even between color in shadows and highlights, and a color ISSUE, which can be an uneven color "cast" across the sensor (magenta corners for example) or uneven across the luminance values (more color in shadows).

A color cast is easy to fix, a color issue such as Ive described is not.

I think we are getting confused between a color CAST, which is an even color tint - even across the frame, and even between color in shadows and highlights, and a color ISSUE, which can be an uneven color "cast" across the sensor (magenta corners for example) or uneven across the luminance values (more color in shadows).

A color cast is easy to fix, a color issue such as Ive described is not.

A color cast is never even. It is as gradual as the environment you are exposing. The white wall for instance appears to be a solid white but infact it is anything but solid. It is a huge gradient. And the fall-off of the lens applies yet another gradient onto the scene which is already an abundance of Radial, Linear and what not gradients. Once light falls off it alters its color AND saturation. Say you shoot a white wall outside and the sun if hitting it from a steep top angel. This will create a gradient (although it may not be visually (by eye) perceived as one). This gradient is not just a luminance gradient but also a color gradient. Shadows have very different colors than mids and highlights. Gamma too. And gamma is the one major factor when blending and saturating colors.

So I know this isn't a very good test but it kind of shows how these pink/magenta corners are affecting the image. This is just shot in prores LT on a canon 24-105 at 400 ISO. All I know is this never looked this way on my BMPC 4k. The magenta on the bottom corners is awful.

Pink%20Corners%20color%201.jpg

This is unacceptable and awful indeed!! Blackmagic needs to swap your camera out! This is way too far out to simply fix in post even if somehow that were possible. Phillip, could you please post a grey open sensor shot using white paper against a window and also with your lens? This looks as bad as my first test when I used a color calibrated lightbox. There are without a doubt, cameras out there with serious sensor issues!

I think we are getting confused between a color CAST, which is an even color tint - even across the frame, and even between color in shadows and highlights, and a color ISSUE, which can be an uneven color "cast" across the sensor (magenta corners for example) or uneven across the luminance values (more color in shadows).

A color cast is easy to fix, a color issue such as Ive described is not.

A color cast is never even. It is as gradual as the environment you are exposing. The white wall for instance appears to be a solid white but infact it is anything but solid. It is a huge gradient. And the fall-off of the lens applies yet another gradient onto the scene which is already an abundance of Radial, Linear and what not gradients. Once light falls off it alters its color AND saturation. Say you shoot a white wall outside and the sun if hitting it from a steep top angel. This will create a gradient (although it may not be visually (by eye) perceived as one). This gradient is not just a luminance gradient but also a color gradient. Shadows have very different colors than mids and highlights. Gamma too. And gamma is the one major factor when blending and saturating colors.

Try and WB this one, I can make it better but can't get rid of it completely at least not with a global white balance. It is on page 7, the image didn't come through with the quote.

I think we are getting confused between a color CAST, which is an even color tint - even across the frame, and even between color in shadows and highlights, and a color ISSUE, which can be an uneven color "cast" across the sensor (magenta corners for example) or uneven across the luminance values (more color in shadows).

A color cast is easy to fix, a color issue such as Ive described is not.

A color cast is never even. It is as gradual as the environment you are exposing. The white wall for instance appears to be a solid white but infact it is anything but solid. It is a huge gradient. And the fall-off of the lens applies yet another gradient onto the scene which is already an abundance of Radial, Linear and what not gradients. Once light falls off it alters its color AND saturation. Say you shoot a white wall outside and the sun if hitting it from a steep top angel. This will create a gradient (although it may not be visually (by eye) perceived as one). This gradient is not just a luminance gradient but also a color gradient. Shadows have very different colors than mids and highlights. Gamma too. And gamma is the one major factor when blending and saturating colors.

...This is absolutley not the reason for the colour cast issue, that we discuss in this thread

So, I feel like ever since I've seen magenta in the corners, I look for it everywhere and now I see it everywhere whether it's there or not. Here's a few clips that I shot in Raw 4:1, 4096x2160 (windowed), 400 ISO, Canon 24-105 (no filters, ND, IR, Etc) (Ursa Mini 4.6k EF). Does anybody see any magenta in the lower right and left corners? I honestly cannot tell anymore, I've been staring at it so much. I feel like I see it, but then I don't. If it is there, then that's saying something because it is windowed. I feel like there's a bunch of factors that go into whether or not the magenta corners show up. Or, they're always there, but certain lighting tends to bring it out more than others. On page 7 of this thread I posted a shot with the same lens looking at a parking lot where there was tons of magenta along the bottom and corners. So I don't know, this whole magenta thing is driving me crazy.

So, I feel like ever since I've seen magenta in the corners, I look for it everywhere and now I see it everywhere whether it's there or not. Here's a few clips that I shot in Raw 4:1, 4096x2160 (windowed), 400 ISO, Canon 24-105 (no filters, ND, IR, Etc) (Ursa Mini 4.6k EF). Does anybody see any magenta in the lower right and left corners? I honestly cannot tell anymore, I've been staring at it so much. I feel like I see it, but then I don't. If it is there, then that's saying something because it is windowed. I feel like there's a bunch of factors that go into whether or not the magenta corners show up. Or, they're always there, but certain lighting tends to bring it out more than others. On page 7 of this thread I posted a shot with the same lens looking at a parking lot where there was tons of magenta along the bottom and corners. So I don't know, this whole magenta thing is driving me crazy.

It's definitely there in both sides but more on the right side top and bottom. It's a repeatable artifact in the same areas of the frame, but it shows stronger or weaker under different conditions.

Mine seems fine I guess, This is with sigma 18-35.

Mine seems fine I guess, This is with sigma 18-35.

Can you post some footage?

So then here's a shot in that same parking lot of the image I posted on page 7.

Just shot this now, pretty bright sun light coming down. I can still see magenta in the corners, but it doesn't look as bad as the shots from the images I posted. This was shot in Raw 4:1, Full sensor at 4.6k, Canon 24-105, 400 iso, f22.

Here is the original Raw file (google drive download), if anyone wants to play with it and see if you can see the magenta corners or get rid of them completely.

https://drive.google.com/file/d/0B858Ua ... sp=sharing

Again, maybe I'm just seeing things, I feel like I can't tell anymore lol.

It looks like the common problem one gets with adapting lenses not designed for the sensor in question. The a7S II and a7R II have this a lot.

The most common explanation I've seen of this is the rays at the corners hit the sensor at an oblique angle, hence causing the magenta shift. Quite common actually.

It would be nice to see the same tests with high end lenses on both the EF and PL mounts. If there's no color cast when the lens is taken off, the sensor is okay. It's a simple test.

What exactly is a high end lens? Can you exactly name it?

+1 for magenta issues. After a 9 month wait period, this is ...

Blank frame is without lens onto a white wall.

Try and WB this one, I can make it better but can't get rid of it completely at least not with a global white balance. It is on page 7, the image didn't come through with the quote.

Hi David, I don't know which one you meant - there were a lot of images on P7.


I picked the Porche Image. Those Magenta Blobs looked interesting. Especially since they were exhibiting irregular behavior... I was NOT able to kill the blobs with a global Neutralization as opposed to the wall shots but had not expected that either given the nature of the localization of the blobs.

I brought down Gamma and increased gain to see what really happens down there.

IMO - I could be wrong of course, if the camera has/had some 'issue' with Magenta should it then not be regular in consistent ? I have commented the 'blobs' and highlighted the "Weirdness" where IMO the Fall Off and Magenta should at least exhibit Magenta - however, it does not the right edge shares the same color as center image.

I can't tell exactly what it is going on here - The RAW image would reveal more. I do know this, this Camera (and others) is capable of capturing nuances that we do NOT perceive while looking at the scene. In most cases, we like those "nuances" as in Cyan in Neutral Colored Objects or the beautiful yellow-orange shimmering off the door which is barely being hit by the sun. In the case of i.e. exhaust or gasoline spots on asphalt which 'could' and I am NOT saying that it is, yield a magenta shimmer. Filters go a long way to get those unwanted nuances out of the image - perhaps BMD does not employ one, I don't know.

Perhaps someone from Black Magic could chime in here or look at all the images posted here. That would be nice...

I'll take my UM46 for thorough spin this week and check in many situations and report back after that...

Here is the weird Porsche Image taken down in Gamma !

BTW - Take a loot at the right side of the roof of the Porsche. When brought down in Gamma its white appear to be Cyan. Does that mean that the UM46 has a Cyan Problem. As I am sure that Porsche never painted it in that color.

magentaBlobs.jpg (872.19 KiB) Viewed 16386 times

...This is absolutley not the reason for the colour cast issue, that we discuss in this thread

OK - Thanks for that insightful piece of information Andreas... Perhaps you would be so good and share your vast knowledge as to exactly why this 'thing' is happening ?


Thanks

Could someone who believes his camera is suffering from the magenta issue - post links to uncompressed CinemaDNGs 4.6k from the following

Early Afternoon with sun in the back on green grass shoot an almost frame covered x-rite or other color chart,
at ALL possible white balance in-camera values @ Aperture 5.6

1 Frame per shot suffices.

If the camera indeed has a Magenta Problem is will reveal its face on those shots.

So then here's a shot in that same parking lot of the image I posted on page 7.

Just shot this now, pretty bright sun light coming down. I can still see magenta in the corners, but it doesn't look as bad as the shots from the images I posted. This was shot in Raw 4:1, Full sensor at 4.6k, Canon 24-105, 400 iso, f22.

Here is the original Raw file (google drive download), if anyone wants to play with it and see if you can see the magenta corners or get rid of them completely.

https://drive.google.com/file/d/0B858Ua ... sp=sharing

Again, maybe I'm just seeing things, I feel like I can't tell anymore lol.

...stil there. But not very strong...

So then here's a shot in that same parking lot of the image I posted on page 7.

Just shot this now, pretty bright sun light coming down. I can still see magenta in the corners, but it doesn't look as bad as the shots from the images I posted. This was shot in Raw 4:1, Full sensor at 4.6k, Canon 24-105, 400 iso, f22.

Here is the original Raw file (google drive download), if anyone wants to play with it and see if you can see the magenta corners or get rid of them completely.

https://drive.google.com/file/d/0B858Ua ... sp=sharing

Again, maybe I'm just seeing things, I feel like I can't tell anymore lol.

...stil there. But not very strong...I think I will give up on this camera. Hope NAB will bring an alternative with wide dynamic range...

So then here's a shot in that same parking lot of the image I posted on page 7.

Just shot this now, pretty bright sun light coming down. I can still see magenta in the corners, but it doesn't look as bad as the shots from the images I posted. This was shot in Raw 4:1, Full sensor at 4.6k, Canon 24-105, 400 iso, f22.

Here is the original Raw file (google drive download), if anyone wants to play with it and see if you can see the magenta corners or get rid of them completely.

https://drive.google.com/file/d/0B858Ua ... sp=sharing

Again, maybe I'm just seeing things, I feel like I can't tell anymore lol.

...stil there. But not very strong...I think I will give up on this camera. Hope NAB will bring an alternative with wide dynamic range...

ALL the frames are corrupted and cannot be used.
Could you post just ONE frame which is not corrupted. Thx

So I just recently shot a music video and I was one of the ones who I guess was deemed to have a pretty decent sensor. I've probably shot at least 7 paid gigs in the 3 weeks or so I've had my Mini. I went searching for it and I dont think its prevalent in my sensor. If it is I think its correctable Magenta is naturally in the daylight spectrum but I dont have the shading / or vignetting like other have posted.
All shots are WB with the standard 4.6K BM Lut added on one node no other corrections.

Sigma 18-35 ISO 200 at f/9 no ND. Yes I shot into the sky with no ND DR is crazy!!! and look at the highlight rolloff. There might be a smidge of magenta in the black on her shirt. If I turn up the green in the lift channel I can easy neutralize that though.

MagTestShoot.jpg (733.22 KiB) Viewed 16376 times

Somebody was saying something about maybe Cheap Rokinon Lenses being a a cause Rokinon Cine DS 85mm at T9-10 ish

MagTestShoot1.jpg (668.27 KiB) Viewed 16376 times

105 Watt Eiko CFL (420 watt equiv.) in a 30 inch Chinaball 3-5 feet above I forget. Rokinon 85mm again at T4

MagTestShoot3.jpg (788.11 KiB) Viewed 16376 times

I dont know if my sensor can be used as a baseline but I dont seem to be exhibiting any magenta issues. And if there are I can definitely pull it out with tint controls, wb, or a qualifier.

Try and WB this one, I can make it better but can't get rid of it completely at least not with a global white balance. It is on page 7, the image didn't come through with the quote.

Hi David, I don't know which one you meant - there were a lot of images on P7.


I picked the Porche Image. Those Magenta Blobs looked interesting. Especially since they were exhibiting irregular behavior... I was NOT able to kill the blobs with a global Neutralization as opposed to the wall shots but had not expected that either given the nature of the localization of the blobs.

I brought down Gamma and increased gain to see what really happens down there.

IMO - I could be wrong of course, if the camera has/had some 'issue' with Magenta should it then not be regular in consistent ? I have commented the 'blobs' and highlighted the "Weirdness" where IMO the Fall Off and Magenta should at least exhibit Magenta - however, it does not the right edge shares the same color as center image.

I can't tell exactly what it is going on here - The RAW image would reveal more. I do know this, this Camera (and others) is capable of capturing nuances that we do NOT perceive while looking at the scene. In most cases, we like those "nuances" as in Cyan in Neutral Colored Objects or the beautiful yellow-orange shimmering off the door which is barely being hit by the sun. In the case of i.e. exhaust or gasoline spots on asphalt which 'could' and I am NOT saying that it is, yield a magenta shimmer. Filters go a long way to get those unwanted nuances out of the image - perhaps BMD does not employ one, I don't know.

Perhaps someone from Black Magic could chime in here or look at all the images posted here. That would be nice...

I'll take my UM46 for thorough spin this week and check in many situations and report back after that...

Here is the weird Porsche Image taken down in Gamma !

BTW - Take a loot at the right side of the roof of the Porsche. When brought down in Gamma its white appear to be Cyan. Does that mean that the UM46 has a Cyan Problem. As I am sure that Porsche never painted it in that color.

magentaBlobs.jpg

This is exactly the issue that is being discussed here, an irregular magenta tinting in the corners which is not an incorrect WB and cannot be simply corrected with a global adjustment. Whatever the reason for it being there it is not normal and not acceptable.

ALL the frames are corrupted and cannot be used.
Could you post just ONE frame which is not corrupted. Thx

They aren't corrupted. It's Raw 4:1 so you have to open it with the latest version of resolve.

This is exactly the issue that is being discussed here, an irregular magenta tinting in the corners which is not an incorrect WB and cannot be simply corrected with a global adjustment. Whatever the reason for it being there it is not normal and not acceptable.

I am using the latest Resolve. I cannot view any of the Frames !

What exactly is a high end lens? Can you exactly name it?

I would prefer to see cine lenses in preferably the PL mount.

So I just recently shot a music video and I was one of the ones who I guess was deemed to have a pretty decent sensor. I've probably shot at least 7 paid gigs in the 3 weeks or so I've had my Mini. I went searching for it and I dont think its prevalent in my sensor. If it is I think its correctable Magenta is naturally in the daylight spectrum but I dont have the shading / or vignetting like other have posted.
All shots are WB with the standard 4.6K BM Lut added on one node no other corrections.

Sigma 18-35 ISO 200 at f/9 no ND. Yes I shot into the sky with no ND DR is crazy!!! and look at the highlight rolloff. There might be a smidge of magenta in the black on her shirt. If I turn up the green in the lift channel I can easy neutralize that though.

MagTestShoot.jpg

Somebody was saying something about maybe Cheap Rokinon Lenses being a a cause Rokinon Cine DS 85mm at T9-10 ish

MagTestShoot1.jpg

105 Watt Eiko CFL (420 watt equiv.) in a 30 inch Chinaball 3-5 feet above I forget. Rokinon 85mm again at T4

MagTestShoot3.jpg

I dont know if my sensor can be used as a baseline but I dont seem to be exhibiting any magenta issues. And if there are I can definitely pull it out with tint controls, wb, or a qualifier.

First frame top right. I don't know if I'm losing it but I'm seeing it everywhere now.

Tested my Ursa Mini 4.6K with a white wall and three different lenses. All at F4. What you see is the upper right corner.

First frame top right. I don't know if I'm losing it but I'm seeing it everywhere now.

An overall cast is there on the entire image but its just a matter of color correction and adjusting the time control. Check her shirt, and the concrete its not even something needs to be graded out. Tighten up the wb and voila

I found this explanation today. The math is over my head, but I could follow at least the first couple pages conceptually, and it explains how the angle of the light (which will also vary with focal length) can cause magenta corners.

This is different than a simple color cast which could be fixed by an offset.

I am curious to do some tests and find my worst case scenario and then see if other owners can use those lens and setting combinations to prove that some of these cameras don't have the issue.

I can say right now, I'd love to see a full frame (not windowed) example of someone shooting clean in Film Mode with a Canon 50mm 1.4 - so far that one seems to be the worst for me. Pulling down the blacks to get back to regular contrast seem to make it much more apparent in my case.

http://www.imagesensors.org/Past%20Work ... t%20al.pdf

First frame top right. I don't know if I'm losing it but I'm seeing it everywhere now.

An overall cast is there on the entire image but its just a matter of color correction and adjusting the time control. Check her shirt, and the concrete its not even something needs to be graded out. Tighten up the wb and voila

I agree that the samples you've posted show an overall magenta cast that is correctable with WB. This is not the same problem or at least not in the same degree that has been showing up in other cameras when blotchy pools of magenta are showing up in the sides and corners. People are reporting having no issues at all with magenta and they have been trying their best to make it show up with under many different conditions and lenses.

Below is an excerpt from a review of the 4.6k by Mark Sturman who is a member of Shane's Inner Circle Facebook forum (Shane Hurlbut ASC https://www.hurlbutvisuals.com/blog/sha ... cle/?tm=ic )

"The more I touch this thing, the more I love it.
I've put this thing through some pretty intense trials to see if it had any of the magenta cast issues in the corners some initial cameras were reporting. I'm seeing none. Zero. And lord did I try! I've shot at white boards, with and without the lens, at all white balance temperatures, in every ISO setting, at all levels of light with different lenses and distances and I'm getting an even color match across the whole screen every time. So, the magenta issue is either an issue they had with the first set of test sensors, or is an issues they've fixed. Could be mine is just one of the "good ones", who knows, but no magenta problems on my end. Which was severely relieving."

His report clearly tells a tale of two or even three different cameras. 1. Clean and unaffected 2. One's that show a bit of peekaboo, but tamable magenta and 3. "Hi, I'm Magenta. I'll just have a seat in the corners, got anything to eat?".

Guys;

I am kind of concerned. I just got our 4.6K after 9 months of waiting - and shot a bunch of test rolls with solid glass.

Zeiss ZF.2 (Duclos modified) 25, 50 + 85 - plus the Canon 70-200.

After I posted some stress tests - people pointed out vignetting and magenta casts. The upper right part of my frame has significantly less exposure... but I thought maybe that was from the mixture of IR and Variable ND - and my matte box getting in the way (it was windy).

I shot a white chart at a studio yesterday - stopped down to 70 on the chart - and with an IR - it's good... but if you expose past 80+ (like in the last shot) everything is magenta aside from the center.

Is this normal???



Thanks, everyone. I have a major job booked in Early may for a good client and need to shoot A+ rolls.

Best.

- Mike

An overall cast is there on the entire image but its just a matter of color correction...

This made me laugh very hard.
How the hell you want to get rid of the dark corners, even if you reduce magenta in post?

Seriously... even a crap DSLR shooting 4K does not have this issue.

this is my BRAND new 4.6K Mini... and i detected NO magenta.
4.6K @ 4:1 Raw.

White-Balanced to 5200K, indoors, shot at a white shelf. Bare sensor, no lens.

There was some minor variation in light, but the small softness of the edges is fine for me.

when i threw on an old Nikon 35mm 2.8 AIS, i got coloring w/ fallout

Below is an excerpt from a review of the 4.6k by Mark Sturman who is a member of Shane's Inner Circle Facebook forum (Shane Hurlbut ASC https://www.hurlbutvisuals.com/blog/sha ... cle/?tm=ic )

"The more I touch this thing, the more I love it.
I've put this thing through some pretty intense trials to see if it had any of the magenta cast issues in the corners some initial cameras were reporting. I'm seeing none. Zero. And lord did I try! I've shot at white boards, with and without the lens, at all white balance temperatures, in every ISO setting, at all levels of light with different lenses and distances and I'm getting an even color match across the whole screen every time. So, the magenta issue is either an issue they had with the first set of test sensors, or is an issues they've fixed. Could be mine is just one of the "good ones", who knows, but no magenta problems on my end. Which was severely relieving."

His report clearly tells a tale of two or even three different cameras. 1. Clean and unaffected 2. One's that show a bit of peekaboo, but tamable magenta and 3. "Hi, I'm Magenta. I'll just have a seat in the corners, got anything to eat?".

Hey Benton,

Any word from BM on how quickly they're gonna send you a new camera?

This is exactly the issue that is being discussed here, an irregular magenta tinting in the corners which is not an incorrect WB and cannot be simply corrected with a global adjustment. Whatever the reason for it being there it is not normal and not acceptable.

I am using the latest Resolve. I cannot view any of the Frames !

That's odd. I just downloaded the file, unzipped it, and it opens just fine in resolve. I got nothin...lol

Hi, everyone.

New hear.

I'd just reached out to Blackmagic and sent over 5 DNG's...

Our studio's new 4.6K is experiencing a really hard to deal with vignette - and on our 25mm Zeiss - the entire right third of the frame (more in the corners) isn't only really magenta - but super dark. When I pan - it looks like the entire image has a vignette filter applied to the middle.

It's impossible to shoot skies or wides as is right now.

On each lens - the vignette changes. It's worse on our Primes than the 70-200 Canon zoom.

I am new and cannot post URLS to the still grabs - but feel free to message me for a link to the Flicker Account I just created to post them.

I shot a white chart exposed to 70 on all our lenses in a studio yesterday - with an IR applied - it looked OK but still had drop off around the corners - at 80 on the cyc, the image just fell apart. We shot at 2.0 to avoid IR pollution.

All of this was shot at 800ISO - the daytime stuff in the stills was shot with an IR and ND - lens at 2.0.

Look forward to feedback. Kinda sick to my stomach about all this today. Have 2 jobs booked with the camera starting in May - and already had waited 9 months for it to arrive.

- Mike

Hi Guys,

I am going to have to stand corrected and take back my initial thoughts towards this topic.

My camera too suffers from some kind of sensor bug. While Magenta is the most obvious symptom there are plenty others.

I have gone ahead and made a repro case in this following thread. It would be interesting if anyone with a URSA Mini 4.6 could try the Repro Case with the Cap on the Turret - to see if each sensor is suffering from the same problem or each sensor is suffering from the same problem but on various parts of the sensors...

Sorry for not if, initially, I came across as doubtful towards those who encountered this problem before I did

http://forum.blackmagicdesign.com/viewtopic.php?f=2&t=46656

- Mike

Mike, I have the same... See the link I posted one up from this one... I have a rectangle of Magenta on the right sensor side...

Can you put your camera in a dark room and place the turret cap on the cam. The shoot a frame @iso 200, shutter angle 45 - WB 6500 and post a link (1 Frame Only) to the uncompressed 4.6k RAW here. I would like to see whether this is identical to mine.

If it is, then there is a huge possibility that all cameras will suffer from this.

Guys;

I am kind of concerned. I just got our 4.6K after 9 months of waiting - and shot a bunch of test rolls with solid glass.

Zeiss ZF.2 (Duclos modified) 25, 50 + 85 - plus the Canon 70-200.

After I posted some stress tests - people pointed out vignetting and magenta casts. The upper right part of my frame has significantly less exposure... but I thought maybe that was from the mixture of IR and Variable ND - and my matte box getting in the way (it was windy).

I shot a white chart at a studio yesterday - stopped down to 70 on the chart - and with an IR - it's good... but if you expose past 80+ (like in the last shot) everything is magenta aside from the center.

Is this normal???



Thanks, everyone. I have a major job booked in Early may for a good client and need to shoot A+ rolls.

Best.

- Mike

Call BM customer support.

I am having the same exact issue...however, I sent my dng files in for review and they said it was normal! I have 5 blackmagic cameras and none have this issue except for the UM46. Has anyone else heard back from support..anyone hear that what they are experiencing is normal???

Below is an excerpt from a review of the 4.6k by Mark Sturman who is a member of Shane's Inner Circle Facebook forum (Shane Hurlbut ASC https://www.hurlbutvisuals.com/blog/sha ... cle/?tm=ic )

"The more I touch this thing, the more I love it.
I've put this thing through some pretty intense trials to see if it had any of the magenta cast issues in the corners some initial cameras were reporting. I'm seeing none. Zero. And lord did I try! I've shot at white boards, with and without the lens, at all white balance temperatures, in every ISO setting, at all levels of light with different lenses and distances and I'm getting an even color match across the whole screen every time. So, the magenta issue is either an issue they had with the first set of test sensors, or is an issues they've fixed. Could be mine is just one of the "good ones", who knows, but no magenta problems on my end. Which was severely relieving."

His report clearly tells a tale of two or even three different cameras. 1. Clean and unaffected 2. One's that show a bit of peekaboo, but tamable magenta and 3. "Hi, I'm Magenta. I'll just have a seat in the corners, got anything to eat?".

Hey Benton,

Any word from BM on how quickly they're gonna send you a new camera?

They are in touch and very supportive, just no official pronouncement just yet on how this will be handled. I have been assured that their engineers are fully engaged with this issue.

I have the magenta vignette, found it on several footage (not all that i can tell). I've sent several RAW frames and screenshots to BM, waiting for their answer on this too.

Maybe its different issues with the sensor, i did your test and mine seems to have a standard pattern of noise.

https://www.dropbox.com/s/lx2llyl19dt9m ... 8.dng?dl=0

An overall cast is there on the entire image but its just a matter of color correction...

This made me laugh very hard.
How the hell you want to get rid of the dark corners, even if you reduce magenta in post?

Seriously... even a crap DSLR shooting 4K does not have this issue.

If you go back and check this thread I dont have Magenta Corners on my sensor.

[Kristian Lam]

There are 2 distinct topics being discussed in this thread.

One topic is that there is a magenta bias in the image. If you have a look at various side by side comparisons of cameras that have been posted online, you will quickly notice that different cameras from different manufacturers lean towards different colour temperatures right out of the box. This is simply how the sensors have been white balanced by default. This can be tweaked and adjusted by users either via tint control adjustments or in their color grading software. There is currently no option for tint control settings in the camera but this is something we can look into as a software update.

The second topic is to do with the magenta corners exhibited in some of the samples posted here. This is not a sensor or hardware issue. Some of you have already correctly pointed out that this has to do with how the light rays are hitting the sensor. This is especially true for lenses that are not telecentric by design. You can find many examples of this happening on many other camera systems and also a myriad of ways to deal with this. The reason there seems to be cameras that exhibit this phenomenon more than other cameras is to do with the combinations of different types of lenses, different aperture or focal length, and even variances between the same model of lenses.

We are always happy to help if you think you have an issue with your camera. The best thing is to contact your local support offices.

So, magenta corners w/o lens is left out in your description or am I missing a point of earlier tests?

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