URSA Mini 4.6k The Original™ Magenta Cast Issue

All the while there is deafening silence from the manufacturer....

That's not a fair representation Andrew.

The product manager has commented in this actual thread. It doesn't get any more senior than Kris.

viewtopic.php?f=2&t=46112&start=100#p268208

JB

Yep, can't disagree and am happy to be called on the 'deafening silence' comment....fair enough.

As for the rest of the post, am saying there is a percentage of a percentage of cameras that have an issue and it seems that people are still questioning these particular owners, how they use the camera, the lens etc....for people that have repeatedly and consistently demonstrated an issue with their individual cameras.

Just reflecting on what motivates my posts.....there are two bandwagons that people seem to want to jump on, one being defend the Vendor and the other being defend the Customer.

All the while there is deafening silence from the manufacturer....

Which boils down to I was right, you were wrong, you can't argue it and won't admit it so side step it and back to your crusade since you lost that battle.

Then John immediately proves you wrong on that point too. Oh dear. Getting embarrassing now.

Nice one Andrew. Hopefully all this trolling isn't getting in the way of actual work and going out and shooting stuff.

Yep, you were right.

And here they are with just a little bit of color added. I REALLY wish BlackMagic would address this soon, or give me some level of comfort that I will have a $5000 camera that actually looks better than my iPhone at some point soon......Please Blackmagic??

Hi Phillip, with what I'm seeing in the examples your posting, your camera clearly has a hardware defect, just as my camera has shone also, only it's possibly worse in your case. Why am I so sure it's a hardware issue? Because we have seen many beautiful examples where there is no trace of magenta at all coming from certain cameras, so a clean image out of the box is certainly possible and it is what every purchaser of this camera paid for and deserves.

Along with the fine looking promo video from John Brawley, I will direct your attention to this music video of Aaron Carter by Tor Johansen of Blackmagic Design:

Aside from the overall fantastic quality, look at the giant grey wall at 0:15, it has no trace of magenta and no vignetting either. This is how it should be!

In my mind the only course of action is replacing any camera that exhibits this cross color cast for a camera that doesn't. Even if Blackmagic came out with a post fix, why should any user have to put up with that when clean cameras are possible and do exist? I have read on more than one occasion that a BM camera owner may have to go through even several Blackmagic cameras until they get a good one that is free from major issues (like the FPN issue on the first 4k version), but once you get a good copy, it's totally worth all the hassle in the long run.

This is how I'm approaching the new 4.6k which is freaking totally amazing when it delivers!! I want that performance like there's no tomorrow and am willing to keep pursuing until I get a winner. With that said, I send mine back in the morning with it's RMA number.

Hey Benton,

The colorist on the Aaron Carter music video at Coyote Post most certainly had the ability to address the issue if it indeed was problematic. We'll never know if that was the case.

The more I test the 4.6K the more I'm impressed with it. I still however experience your issue at full res. Hopefully I'll hear back from support in a timely manner.

Hey Benton,

The colorist on the Aaron Carter music video at Coyote Post most certainly had the ability to address the issue if it indeed was problematic. We'll never know if that was the case.

The more I test the 4.6K the more I'm impressed with it. I still however experience your issue at full res. Hopefully I'll hear back from support in a timely manner.

I'm sure a skillful colorist could fix most any issue (with a cross color curve being one of the toughest), but according to Tor Johansen he experienced no color issues at all.

Hey Benton,

The colorist on the Aaron Carter music video at Coyote Post most certainly had the ability to address the issue if it indeed was problematic. We'll never know if that was the case.

The more I test the 4.6K the more I'm impressed with it. I still however experience your issue at full res. Hopefully I'll hear back from support in a timely manner.

I'm sure a skillful colorist could fix any issues (with a cross color curve being one of the toughest), but according to Tor Johansen he experienced no color issues at all.

Interesting... The dudes at Coyote Post are awesome, that's certainly a biased statement but I see your point. Excited to see BM's response on this issue.

And here they are with just a little bit of color added. I REALLY wish BlackMagic would address this soon, or give me some level of comfort that I will have a $5000 camera that actually looks better than my iPhone at some point soon......Please Blackmagic??

Hi Phillip, with what I'm seeing in the examples your posting, your camera clearly has a hardware defect, just as my camera has shone also, only it's possibly worse in your case. Why am I so sure it's a hardware issue? Because we have seen many beautiful examples where there is no trace of magenta at all coming from certain cameras, so a clean image out of the box is certainly possible and it is what every purchaser of this camera paid for and deserves.

Along with the fine looking promo video from John Brawley, I will direct your attention to this music video of Aaron Carter by Tor Johansen of Blackmagic Design:

Aside from the overall fantastic quality, look at the giant grey wall at 0:15, it has no trace of magenta and no vignetting either. This is how it should be!

In my mind the only course of action is replacing any camera that exhibits this cross color cast for a camera that doesn't. Even if Blackmagic came out with a post fix, why should any user have to put up with that when clean cameras are possible and do exist? I have read on more than one occasion that a BM camera owner may have to go through even several Blackmagic cameras until they get a good one that is free from major issues (like the FPN issue on the first 4k version), but once you get a good copy, it's totally worth all the hassle in the long run.

This is how I'm approaching the new 4.6k which is freaking totally amazing when it delivers!! I want that performance like there's no tomorrow and am willing to keep pursuing until I get a winner. With that said, I send mine back in the morning with it's RMA number.

Hey Benton,

Did BM give you an RMA and tell you to send it back? When I sent them my pictures they just said the engineers are aware of the issue and they're looking into it and that I should just use different lenses or fix it in resolve for now (not very helpful). Then when I asked if I should keep checking in or if they would contact me to let me know if I should send my camera in they never responded

Seems maybe there are a couple different opinions in relation to 'Deafening Silence'.....

Seems maybe there are a couple different opinions in relation to 'Deafening Silence'.....

If you're interpreting my response as an example of 'deafening silence' you'd be mistaken. The dialogue between Blackmagic support and myself has been quite good. I don't expect a complex issue like this to be solved in a matter of weeks, however I'm certainly anxious about the result. Patiently optimistic would be my attitude. They're not ignoring us.

Seems maybe there are a couple different opinions in relation to 'Deafening Silence'.....

If you're interpreting my response as an example of 'deafening silence' you'd be mistaken. The dialogue between Blackmagic support and myself has been quite good. I don't expect a complex issue like this to be solved in a matter of weeks, however I'm certainly anxious about the result. Patiently optimistic would be my attitude. They're not ignoring us.

Fair enough...I am patiently waiting to place my order.

Hey Benton,

Did BM give you an RMA and tell you to send it back? When I sent them my pictures they just said the engineers are aware of the issue and they're looking into it and that I should just use different lenses or fix it in resolve for now (not very helpful). Then when I asked if I should keep checking in or if they would contact me to let me know if I should send my camera in they never responded

I simply told them (Paraphrasing) I wanted a replacement based on the fact that many people have reported no color issues and there are plenty of examples of clean cameras out there. Josh Stroh (my contact) in technical support didn't argue and said: "Absolutely. I've included the necessary (RMA) form below." They might announce some other approach in the future, maybe even a recall (pure speculation) but if you want a replacement camera now, you have to ask for one. I also asked if they could check out my new replacement before shipping to ensure it has no color cast, but have gotten no reply on that yet.

Seems maybe there are a couple different opinions in relation to 'Deafening Silence'.....

If you're interpreting my response as an example of 'deafening silence' you'd be mistaken. The dialogue between Blackmagic support and myself has been quite good. I don't expect a complex issue like this to be solved in a matter of weeks, however I'm certainly anxious about the result. Patiently optimistic would be my attitude. They're not ignoring us.

Fair enough...I am patiently waiting to place my order.

...BMD should create a service workflow for that issue, so that people can exchange cameras (with a proofen magenta cast) for a new one. Until that, I would not buy the 4.6K Mini.

Hey guys, I just did a little Vignette/Magenta Test with my Ursa Mini 4.6 and uploaded the .dng files.
I shot with no lense and a 24-70mm Canon II.

Right now I don't have the option to play around with the files so it would be great if you can tell me what you think. I have the option to bring back the camera on monday and get the next delivery. So what should I do? There is a bit magenta and definitely a vignette on all four corners even without a lense.

Would be great if you can tell me what you think.

ISO: 800
Frame Guides: 1.85:1

Link: https://we.tl/IpaVrs2eTV


1. without lense paper
2. without lense wall
3. 24mm wall focus
4. 24mm wall defocused
5. 70mm wall focus
6. 70mm wall defocused
7. 24mm paper
8. 70mm paper

I'm in for magenta.
That's how it looks on Sigma 18-35


And here with Zeiss Planar T* 50mm


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

This probably WONT be the case BUT I thought I'd mention it just in case

I had magenta on my URSA Mini 4.6K --- The reason was the Tally light on the viewfinder

I turned off the tally light and gone was the Magenta !!!

The design of the Viewfinder is a little unfortunate regarding the tally light. If one use a short flange lens like a Zeiss 50mm. The Tally light will shine into the lens as the Viewfinder extends about a tally length over the lens.
Personally I can't think of ANY reason where that light would NOT be an utter nuisance when shooting unless one loves to be able to show off when he is recording

If Magenta is an issue otherwise, it is a problem with the green channel. Which with all respect has been a problem with BMD Cameras since the get go.

Since the BMCC and with the BMPC and now the URSA - In dark scenes Green is off causing greenish images, in bright scenes green is off causing magenta's images. It is probably a problem with the designated black level of the Camera and balancing the Linearization curve.

DO you guys have the problem when shooting Film mode (Log) or with Video Mode, or both ?

Hey Benton,

Did BM give you an RMA and tell you to send it back? When I sent them my pictures they just said the engineers are aware of the issue and they're looking into it and that I should just use different lenses or fix it in resolve for now (not very helpful). Then when I asked if I should keep checking in or if they would contact me to let me know if I should send my camera in they never responded

I simply told them (Paraphrasing) I wanted a replacement based on the fact that many people have reported no color issues and there are plenty of examples of clean cameras out there. Josh Stroh (my contact) in technical support didn't argue and said: "Absolutely. I've included the necessary (RMA) form below." They might announce some other approach in the future, maybe even a recall (pure speculation) but if you want a replacement camera now, you have to ask for one. I also asked if they could check out my new replacement before shipping to ensure it has no color cast, but have gotten no reply on that yet.

Hey Benton,

That sounds like good news. What's Josh's contact? He sounds like the person I need to talk to

I turned off the tally light and gone was the Magenta !!!

Anybody else?

I'm following the magenta issue closely as I wanted to buy a 4.6K but holding off until there is more information about it, I was next in line at PCEngineering in the USA but had to step out for now.

Anyone who's experiencing this problem, or isn't should share the lens they used, any specific focal length if it was a zoom, and the aperture setting. Also indicate if any extra lens mount adapter was in use on top of the EF. The PL's are shipping now so again, users should specific which model URSA mini 4.6K they have.

I had a local guy here in Toronto do the test really quick and on his 4.6K there was absolutely no magenta cornering, only a subtly fall off which is normal. Even my Sony F55 does this a little bit.

I also question whether the "white paper" test is practical, it could actually amplify the issue that you might not have if you had been using an actual lens. With paper the light is going to scatter more than to be directed by the rear element of a lens.

If feels like to me that the distance and size of the rear lens element to the sensor plane contributes to this problem. My theories are highly speculative obviously, based on the limited amount of information that we all have right now.

One thing I just saw posted on Facebook was an actual video on a 4.6K mini with Sigma 18-35mm where zoomed in you see magenta cornering and then as the focal length is changed to wide the magenta cornering goes away almost entirely:

Hey Benton,

Did BM give you an RMA and tell you to send it back? When I sent them my pictures they just said the engineers are aware of the issue and they're looking into it and that I should just use different lenses or fix it in resolve for now (not very helpful). Then when I asked if I should keep checking in or if they would contact me to let me know if I should send my camera in they never responded

I simply told them (Paraphrasing) I wanted a replacement based on the fact that many people have reported no color issues and there are plenty of examples of clean cameras out there. Josh Stroh (my contact) in technical support didn't argue and said: "Absolutely. I've included the necessary (RMA) form below." They might announce some other approach in the future, maybe even a recall (pure speculation) but if you want a replacement camera now, you have to ask for one. I also asked if they could check out my new replacement before shipping to ensure it has no color cast, but have gotten no reply on that yet.

Hey Benton,

That sounds like good news. What's Josh's contact? He sounds like the person I need to talk to

Josh Stroh's email is: support-usa@blackmagicdesign.com This is the address his replys are coming from, but I don't know if this goes to him directly so you may want to put attention to Josh in the subject line. Good luck!

@Dennis Hingsberg
Now that Facebook posting by Maarten Smeenk has to be an unexpected but important finding. If the magenta is related to light scattering, I would have thought the 18mm focal length would be a more likely cause than the observed 35mm! Everyday we learn something here. Perhaps a few enterprising folks (who are experiencing the fringing or magenta vignetting) would like to post more results using a variety of focal lengths with either prime or zoom lenses. The plot thickens. Where is Sherlock Holmes?


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Hey Benton,

That sounds like good news. What's Josh's contact? He sounds like the person I need to talk to

Josh Stroh's email is: support-usa@blackmagicdesign.com This is the address his replys are coming from, but I don't know if this goes to him directly so you may want to put attention to Josh in the subject line. Good luck!

Thanks man! I'm curious to see how quickly they get you a new one and whether it's magenta free or not....keep me posted!

@Dennis Hingsberg
Now that Facebook posting by Maarten Smeenk has to be an unexpected but important finding. If the magenta is related to light scattering, I would have thought the 18mm focal length would be a more likely cause than the observed 35mm! Everyday we learn something here. Perhaps a few enterprising folks (who are experiencing the fringing or magenta vignetting) would like to post more results using a variety of focal lengths with either prime or zoom lenses. The plot thickens. Where is Sherlock Holmes?


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Has been a bit of this discussed previously....but in reverse :-

http://www.bmcuser.com/showthread.php?1 ... post197960

I suspect BMD know and understand the cause exactly, but by remaining low key about it then the effect is for speculation to thrive.

In hindsight, what I see is more Magenta where there is more falloff....evenly lit across the frame presents itself as a color cast, which is relatively easy to grade out.

Uneven falloff or shading, becomes 3D and gets real complicated real quick.

@Dennis Hingsberg
Now that Facebook posting by Maarten Smeenk has to be an unexpected but important finding. If the magenta is related to light scattering, I would have thought the 18mm focal length would be a more likely cause than the observed 35mm! Everyday we learn something here. Perhaps a few enterprising folks (who are experiencing the fringing or magenta vignetting) would like to post more results using a variety of focal lengths with either prime or zoom lenses. The plot thickens. Where is Sherlock Holmes?

Yes we need to see varying focal length but varying apertures as well. For example at 18mm does F2.8 exhibit it more or less magenta corners than say at F5.6, same at 35mm, etc.. and so on and so on. This explains why so many users don't see it, while others do, then we all come here and fight and try to hang the guy who says there is in fact a problem.

Combine that the fact that rear element width vary, distance to the sensor plane vary, all which sets your light path angle and we need more than Sherlock Holmes to solve this - we need Steven Hawking!

Has been a bit of this discussed previously....but in reverse :-

http://www.bmcuser.com/showthread.php?1 ... post197960

I suspect BMD know and understand the cause exactly, but by remaining low key about it then the effect is for speculation to thrive.

In hindsight, what I see is more Magenta where there is more falloff....evenly lit across the frame presents itself as a color cast, which is relatively easy to grade out.

Uneven falloff or shading, becomes 3D and gets real complicated real quick.

Will check that link out thanks.

Perhaps this is why BMD decides to leave out IR and AA filters - from what I read uneven light angles only make things worse in terms of color casts and processing the images off a sensor. Maybe this is what we pay for when we look at camera's which cost substantially more, if these corner color casts are normal traits it means other manufacturers could be compensating for them in real-time with advanced DSP. That is crazy if true.

Posted this elsewhere but is also worth remembering that Magenta is a mix of colors and not Monochromatic. Sure there are colorists who would have no trouble grading this out but for most it will be pretty difficult :-

image.jpeg (16.16 KiB) Viewed 17936 times

http://lodev.org/cgtutor/color.html

http://banksiansphere.blogspot.com.au/2 ... chive.html


If you are keen to 'see' what you see versus what you think you see, then try this game...kinda like a calibration for your eyes.

http://www.colormunki.com/game/huetest_kiosk

We're talking about different issues that have similar image outcomes.

There is....

1. Sensor Shading

and

2. lens shading

Both of these are "google-able" issues that you can easily look for examples of...

and we also seem to have here.....jb

Indeed - https://www.pco.de/fileadmin/user_uploa ... 0603_s.pdf

We're talking about different issues that have similar image outcomes.

There is....

1. Sensor Shading

and

2. lens shading

Both of these are "google-able" issues that you can easily look for examples of...

and we also seem to have here.....jb

Indeed - https://www.pco.de/fileadmin/user_uploa ... 0603_s.pdf

Wow Gene, nice find and especially think this section on 'manufacturer compensation' is pertinent as it is relevant to both CCD and CMOS and it seems to have been a known issue for some time.

ManufacturerCompensation.JPG (33.12 KiB) Viewed 17892 times

Note how massive an impact on Quantum Efficiency the use of a microlens can and does have (difference between the blue and red lines)

CoverGlass.JPG (102.15 KiB) Viewed 17887 times

Andrew, it would seem to me that if you wanted to test this issue scientifically, you would need to know the CRA (Chief Ray Angle) of the UM46 sensor and use a lens close to the same CRA. Otherwise one should expect falloff in intensity as you move from the geometric center of the sensor.

As I mentioned earlier, LENS SHADING and SENSOR shading compound these issues.

This is why more telecentric lens designs are important for digital formats (like mft), while holding onto legacy formats like 135 "full frame" and PL are more problematic. This is the DOWNSIDE of having compatibility with all the "analog" lenses.

JB

As I mentioned earlier, LENS SHADING and SENSOR shading compound these issues.

This is why more telecentric lens designs are important for digital formats (like mft), while holding onto legacy formats like 135 "full frame" and PL are more problematic. This is the DOWNSIDE of having compatibility with all the "analog" lenses.

JB

There you go...this whole time I have read you mention 'telecentric lens designs' a few times here and there and never bothered to actually go and read up on the meaning behind the meaning. Is actually very interesting to understand how this has developed over time.

Am sure you don't need me to tell you, as you are way more skilled than most, especially including myself....but the idea we now have the possibility to attach 'any lens' to 'any camera' is something beyond what I think was envisaged when camera and lens engineers got together.

So how do customers weed out say an actual camera problem versus 'Philosophy of Use'...

As I mentioned earlier, LENS SHADING and SENSOR shading compound these issues.

This is why more telecentric lens designs are important for digital formats (like mft), while holding onto legacy formats like 135 "full frame" and PL are more problematic. This is the DOWNSIDE of having compatibility with all the "analog" lenses.

JB

There you go...this whole time I have read you mention 'telecentric lens designs' a few times here and there and never bothered to actually go and read up on the meaning behind the meaning. Is actually very interesting to understand how this has developed over time.

Am sure you don't need me to tell you, as you are way more skilled than most, especially including myself....but the idea we now have the possibility to attach 'any lens' to 'any camera' is something beyond what I think was envisaged when camera and lens engineers got together.

So how do customers weed out say an actual camera problem versus 'Philosophy of Use'...

I would say for now, it takes some threads just like already exist for ND/IR filters, EF lenses and CFast cards. Assuming that part of this issue is lens and sensor shading (vs. QC issues), we need to begin to test which lenses play well with the 4.6 sensor and which do not.

Andrew, what John might be trying to say is that digital sensors are much more sensitive to CRA than film was. I wonder if BM has two different versions of their UM46 sensor, one for the EF mount and one for the PL mount?

Another interesting description of CRA - http://space.ednchina.com/Upload/2009/9 ... 1f128f.pdf

Andrew, what John might be trying to say is that digital sensors are much more sensitive to CRA than film was. I wonder if BM has two different versions of their UM46 sensor, one for the EF mount and one for the PL mount?

Another interesting description of CRA - http://space.ednchina.com/Upload/2009/9 ... 1f128f.pdf

Yeah this was the 'light going off above my head' as CRA would make stuff all difference to Film and its isotopic response. Hmmm ....lenses ain't just lenses, yet with all these adapters we can use any lens on almost any camera.

Is interesting as I have almost perfect color vision, if not perfect....and was able to fix all but a couple of the 'white paper' no lens tests within seconds. Then there were a couple that kept me entertained for hours (;->

Well nothing is perfect.

Manufactures fudge things all the time with specs. I know I've tested lenses that don't get to the T stop that's engraved on the lens.

An easy way to see what a lens does is to put false colour up on a flat field (like a wall) and look at how much the corners fall off.

This is a particularly bad example, but this is a RED from a shoot of mine years ago with an angenieux 16-42 T2.8. If you know your false colours then you can work out the flatness here....

Angeniuex lens flatness by John Brawley, on Flickr

JB

Here's the thing.

A lot of this stuff is actually known to many practitioners. Cinematographers. It's not exactly news that lenses fall off in the corners, aren't flat across the field and also have issues of their own with regards to shading along with sensor shading.

No disrespect intended but we've been "putting up" with this for years and we know it's there and we get on with making nice pictures.

While I don't disagree that there is an issue in some certain instances, in many posts it's also a bit of "cry wolf".

Now I see some have pretty much said the issue was ridiculed by those that are EXPERIENCED because, well, it's not like it's not a problem that hasn't been seen before in some way or other.

But because we say "it's not that unusual" or It doesn't show up in actual real world work, we're accused of a conspiracy to "hide" this stuff. As you've already seen, you just have to google lens shading and sensor shading and actually try replicating this test on other cameras to see it's not specific to BM.

Think about the first time you saw and understood what RS was as an image artefact. Once you know it's there you see it EVERYWHERE, but for a lot of people, they are kind of "blind" to it until they are shown what it is.

It's degrees of severity. It's also some that are beyond spec, but a lot of the posted examples in this thread to me, aren't beyond what I would think of as "normal".

JB

Always appreciate the education...in relation to what has come before, isn't 'shading' something that has been considered and built into many digital cameras for some time, yet in the case of the 4.6K this issue is kinda being left as a bit of "find it out for yourself" ?

The light that went off in my head wasn't so much the cause of the shading issue being from lenses or micro lenses....it was that this has been a known problem since almost the dawn of digital image capture and was struggling to understand the different perspectives i

You are perfectly correct that this is something that the more experienced have been aware of and from memory this JVC camera was released in 2003 (yep 13 years ago) and came with a built in 'shading' option in the menu.....for obvious reasons I suspect.

"There are cases when white balance is achieved for the centre of the screen but not for the upper and lowerends, hence causing other colours to appear with green or magenta. This is brought about by the lens characteristics. The process of rectifying this is known as white shading."

http://pro.jvc.com/prof/attributes/pres ... =MDL101387

image.png (74.74 KiB) Viewed 17842 times

"1. Shoot a white subject so that the entire screen is filled with white. (Illumination should be
uniform.)
2.Adjust the white balance.
3. Click the Waveform window button in the toolbar of the KY-LINK screen to display the set-
ting screen. Click the [V] and [R] button to display the waveform of the red channel in the
vertical direction.
4. Adjust the shutter speed, etc. until the video signal level becomes about 170 – 190.
5. On the white balance setting screen, set the Shading item to “ON”.
6. Adjust Level (R) to make the gradient of the waveform as small as possible.
7. Click the [G] button on the setting screen to switch to the waveform of the green channel.
Then adjust Level (G) to make the gradient of the waveform as small as possible.
8. Click the [B] button on the setting screen to switch to the waveform of the blue channel.
Then adjust Level (B) to make the gradient of the waveform as small as possible.
9. When adjustment of the white shading is completed, adjust the white balance.

http://pro.jvc.com/prof/attributes/feat ... ture_id=01

P.s. Started a little business once and the funny thing is that I think I threw one of these out only like 6 months or so ago !

Hi Andrew.

Lens shading tends to be a feature you see on "broadcast" cameras, usually because I believe that broadcast cameras are more susceptible to it because of the way the alignment of 3 CCDs work through a PRISM. In fact a lot of 2/3" lenses have some pretty terrible "faults" and they were fixed by shading correction in camera.

A lot of the Sony cameras still seem to have this correction "feature" but a lot of cinema cameras don't have "manual" shading. It's a bit like FPN, or black shading correction. That's not to say they don't have a sensor level shading correction, they just don't have a manual control to override or set it yourself. Alexa doesn't have it (or manual black shading either) and I'm pretty sure RED don't either (but do have manual shading based on user choices about operating tempreture)

JB

Do we know if the 4.6K sensor is using micro lenses?
Do we know if the micro lenses are all in an identical position in terms of covering the photosite?

If yes, then how do we ever know if any lenses are telecentric to take advantage of that uniform micro lens design?

Are BMD sensors using micro lenses that are shifted at the edges to pick up more light from higher CRA?

If they are shifted do we know the most ideal focal lengths to minimize this problem of a falloff in light?

Do we know if BMD colour science includes anything that compensates for falloff?

All of these explanations don't explain why this is suddenly such a big issue on the 4.6K sensor unless it's simply because of the physically larger size of the true Super 35 sensor. The Super 16 sensors fare better because they're smaller? But is that true because on the Super 16 sensors we use even shorter focal length lenses which have higher CRA, right?

Thanks, Gene and John, for the explanations of what might be contributing to the greater falloff, but we are not seeing all 4.6K sensors behave identically even in terms of falloff let alone in terms of colour variations. Would be interesting to know what's going on behind the scenes that accounts for the variations. Or maybe the variations are due to different focal lengths and apertures and whether or not one has the Blackmagic Viewfinder tally light shining onto the front of the lens.


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No doubt if you have followed this thread, then some of these waveforms and their shapes might look familiar to some of you...maybe we should change the name of this thread to 'White Shading 101'

image.png (8.58 KiB) Viewed 17787 times

http://pro-av.panasonic.net/en/varicam/ ... _04_03.htm

Thanks, Gene and John, for the explanations of what might be contributing to the greater falloff, but we are not seeing all 4.6K sensors behave identically even in terms of falloff let alone in terms of colour variations. Would be interesting to know what's going on behind the scenes that accounts for the variations. Or maybe the variations are due to different focal lengths and apertures and whether or not one has the Blackmagic Viewfinder tally light shining onto the front of the lens.

I think we are wildly speculating about stuff most of us don't even know or understand.

Let's wait and see what BM have to say. They have form for fixing issues like this pretty quickly I think we'll hear something about it.

You also get the same issues byt he way no matter if you have micro lenses or not. It's just an "illustrative" example of how we're talking about a confluence of several issues which all result in magenta footage. Im not saying that any of them ARE the answer...just that there's many possible answers.

JB

Agree it's a confluence of many factors. Fascinating stuff.


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Thanks, Gene and John, for the explanations of what might be contributing to the greater falloff, but we are not seeing all 4.6K sensors behave identically even in terms of falloff let alone in terms of colour variations. Would be interesting to know what's going on behind the scenes that accounts for the variations. Or maybe the variations are due to different focal lengths and apertures and whether or not one has the Blackmagic Viewfinder tally light shining onto the front of the lens.

I think we are wildly speculating about stuff most of us don't even know or understand.

Let's wait and see what BM have to say. They have form for fixing issues like this pretty quickly I think we'll hear something about it.

You also get the same issues byt he way no matter if you have micro lenses or not. It's just an "illustrative" example of how we're talking about a confluence of several issues which all result in magenta footage. Im not saying that any of them ARE the answer...just that there's many possible answers.

JB

Didn't see much in the way of speculation in relation to the post, more like it would just be good to know more ?

But I guess this is why I always seem to get 'Does not follow instructions'.....

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 ?

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 ?

..seems like that...

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 believe all cameras exhibit this potential but only in certain scenarios. I got my Mini 4.6K on Friday night - so I am still investigating. I AM able to repro this scenario under given circumstances - I do believe it has to do with how 'hot' the image was exposed when gathering light where green [luminance] was predominant.

Question to those who have been posting -- Are you all viewing the Imagery in Resolve ?

Is there any theory to support we might see this issue crop up more with full frame lenses vs APC-S or vice versa?

I've seen two videos now with 4.6K of random shots without any vignetting or magenta corners and both used a variety of Canon zooms.. just a thought.

No magenta or vignetting on our first camera. Going to test the 2nd camera this week


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No magenta or vignetting on our first camera. Going to test the 2nd camera this week

That's great news.

Now It'd be very helpful if you could give more information. ie. what lens(es), what test did you perform, what focal length, what f-stop, what…. .

Mine arrives mon or tues. I have the same Sigma 16-35 lens, so I'm def gonna give it a test. Ive seen it more apparent in the Sigma 16-35 in some shots on here, so here's hoping I'm wrong...

No magenta or vignetting on our first camera. Going to test the 2nd camera this week

Would it be possible for you to post a test .dng here? It would be great to see how a good unit is supposed to look like! Thanks!

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