serious moire issues have halted production

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Troy Wuelfing

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serious moire issues have halted production

PostMon Nov 20, 2017 5:20 pm

We have recently purchased two Ursa Mini Pro 4.6 and are having serious moire issues,
so bad in fact that we had to shut down production and will have to get rid of the cameras if we cant find a solution.

i was shocked how bad it is, I am waiting on our DIT to send a few samples and will post them as soon as I get them.

I am curious if anyone else has had these issues and if anyone has found any workarounds.
or an OLPF i can have sent overnight to me as of today.

thanks so much for any help any help anyone can provide, we are in a real jam here.
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Robert Niessner

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Re: serious moire issues have halted production

PostMon Nov 20, 2017 5:52 pm

There is a OLPF from Mosaic Engineering, but I have no idea if and how fast they will deliver - it is a small company only. And I am not even sure if the filter is available yet.

http://store.mosaicengineering.com/VAF- ... p_46.html#

Oh, and you should be aware of that other cameras do have aliasing problems, too:
http://www.cinematography.net/CE-2017%20STILLS.html
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Troy Wuelfing

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Re: serious moire issues have halted production

PostMon Nov 20, 2017 8:01 pm

I contacted mosaic, they do not have them manufactured yet, so this isn't a option. The guy was super nice to speak with though and I hope he brings them to market as it's sorely needed.
Thanks for the suggestion though.

Unless I'm missing something then this camera is really really bad at filming textiles...
I'm aware of this issue not being unique, but it's pretty extreme with this one.
And no OLPF makes things difficult.
Why not even have this as an option?
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JasonFinnigan

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Re: serious moire issues have halted production

PostMon Nov 20, 2017 9:02 pm

Troy Wuelfing wrote:Unless I'm missing something then this camera is really really bad at filming textiles...


It depends on how tight the patterns are.
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Denny Smith

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Re: serious moire issues have halted production

PostMon Nov 20, 2017 9:56 pm

What lens are your using? You could also try using a Sift FX filter, or something similar to reduce the moire’ pattern. What is probably making this an issue with the UM, is the high resolving ability of the 4.6K sensor. Working in TV, we had a list of textile patterns that were not a,lowed for this very reason, so it is not something new or unique to the UM.
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rick.lang

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Re: serious moire issues have halted production

PostMon Nov 20, 2017 10:30 pm

Troy results will vary with the textiles. Rayón likely the worst, cotton probably no problem. Do you have the ability to select the textiles?


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Leon Benzakein

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Re: serious moire issues have halted production

PostMon Nov 20, 2017 10:41 pm

Could turning down the detail in the cameras help with this problem?
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Uli Plank

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 2:45 am

RAW has no 'Detail' aka sharpness.
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rick.lang

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 4:35 am

You can turn down the raw sharpness in DaVinci Resolve. Worth a try.


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Stephen Press

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 6:34 am

I noticed some moire today... took the camera half a step back and it was gone... but sure guess I could have stopped production... one or the other :roll:
"A cameraman with out a camera is just a man"
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Troy Wuelfing

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 10:34 am

i can appreciate your situation of being able to move the camera a half step back to remove the moire.
we are filming a few thousand products with various textiles and things cant move or shift.
our subjects / heros are the textiles, and the camera is locked off and framing set.

it seems as though an OLPF should be created for this camera, the excuse of "shoot around it" is easy to say but not possible for our situation, a real solution which addresses the artifact issue would be preferred.

does anyone know why blackmagic doesnt make one?
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Robert Niessner

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 12:18 pm

Troy Wuelfing wrote:i can appreciate your situation of being able to move the camera a half step back to remove the moire.
we are filming a few thousand products with various textiles and things cant move or shift.
our subjects / heros are the textiles, and the camera is locked off and framing set.

it seems as though an OLPF should be created for this camera, the excuse of "shoot around it" is easy to say but not possible for our situation, a real solution which addresses the artifact issue would be preferred.

does anyone know why blackmagic doesnt make one?


It is VERY difficult and time consuming to make an OLPF fitting for a sensor. There is a reason why it takes Mosaic Engineering so long and why there is now a version 3 of the OLPF.
As Blackmagic cameras are designed for a great price/performance ratio there are certain things where they have to cut costs - and I think an OLPF is one of them.

However, I've successfully removed moire by using NeatVideo and its temporal filter combined with the spatial filtering of chroma only. This might work for you too.
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Troy Wuelfing

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 1:17 pm

Robert Niessner wrote:
Troy Wuelfing wrote:It is VERY difficult and time consuming to make an OLPF fitting for a sensor. There is a reason why it takes Mosaic Engineering so long and why there is now a version 3 of the OLPF


I understand its challenging and can appreciate the price point, but black magic is now a camera company too, and I am of the opinion that this item should be sold as an option. the work can be contracted to a lab or firm that has the expertise if blackmagic doesn't have it in house, but to leave people without a solution for filming textiles is pretty crummy.

The cameras we have are performing great, except this one issue. It just happens that for us this one issue is a deal breaker.
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Wayne Steven

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 1:50 pm

You could try to emulate a low pass filter by putting it minutely out of focus (we are talking under a pixel to a number of pixels). If you go too far it will smudge out the detail. I have suggested this to camera manufacturers before, but none have taken me up on it yet.

But seriously, converting 4.6k down to UHD, doesnt do much for it? That is one of the reasons for over sampling, to reduce things. The only other thing is to change the framing of the image so the pixels don't interpolate with the textures sizes, but you can't really do that.

I guess it might be difficult to figure out a really good camera for filming it, but there must be cameras used in your part of the industry, or on fashion shoots, with good reputation you can look up Troy. There are numerous high end still cameras coming with 4k etc, and gh5 has 6k, but apart from being 'upbeat' the image might not be too your taste. But then the extra step is the Red Helium sensor cameras (just remember to use the recommended color of lighting to get great results in grading). Red offers a number of low pass filters that can be tried in this cameras, which they might be able to advise. Some may give quirks under certain situations, but would better suite other situations. The helium is a grade above in performance, and high end 8k versions are available. Is it worth renting one if the range to try it to see?
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Troy Wuelfing

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 2:11 pm

we are going to test a red camera as it has multiple OLPFs available.
the artifacting is rather substantial and we don't see a way to clear it in post without causing other issues, that said we have not had time to do a lot of experiments so its very possible there is a work around.

the raw file was over the size limit so I couldn't upload it, but the jpg is untouched other than exporting it as a jpg using photoshops raw interpreter. We see the same issue in resolve and premiere just to verify its not photoshop.

I added the first file to make the pattern super apparent since I cant share the raw as its too big.
A999_11211500_C001_000500-extreme levels.jpg
A999_11211500_C001_000500-extreme levels.jpg (223.19 KiB) Viewed 1912 times


A999_11211500_C001_000500-original.jpg
A999_11211500_C001_000500-original.jpg (131.11 KiB) Viewed 1912 times
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Re: serious moire issues have halted production

PostTue Nov 21, 2017 2:33 pm

Changing the Demosaic/Debayering pattern could also potentially help. Here are some examples of how the same frame renders differently based of the application, and if possible to change some of the demosaic/debayering algorithms. In my opinion the opposing frequency technique I used for the last example produced the most consistent solution for multiple frames.
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Demosaic sample comparison.jpg
Demosaic sample comparison.jpg (765.7 KiB) Viewed 1878 times
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Bill Young

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 2:48 pm

I think I might be able to solve this fairly easily, but would need a sample Raw DNG frame to look at the debayer pattern.
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Troy Wuelfing

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 5:05 pm

Bill Young wrote:I think I might be able to solve this fairly easily, but would need a sample Raw DNG frame to look at the debayer pattern.


here is a link to some raw files
https://drive.google.com/open?id=1iFJWA ... 7aIrzhMVaI

look in the inside upper corner of the closest sofa segment
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Re: serious moire issues have halted production

PostTue Nov 21, 2017 7:04 pm

Sadly this doesn't look like debayer/demosaicing moire as the pattern stays consistent using every demosaic/debayer method I have access to. I was able to use destructive noise reduction methods to remove most of the noise, but I doubt you want to go that route, sorry.
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Dmitry Shijan

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Re: serious moire issues have halted production

PostTue Nov 21, 2017 9:49 pm

RAW without OLPF is a pain.
You can try shift image X/Y position to 0.5 px. This removes Cross Hatching effect and and makes moire slightly less visible.
Also people calm that shootng ProRes downsampled in camera to HD or 2K produce very clear image.
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Jamie LeJeune

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 2:55 am

Robert Niessner wrote: I've successfully removed moire by using NeatVideo and its temporal filter combined with the spatial filtering of chroma only. This might work for you too.


I've salvaged shots using the same technique.

However, I wouldn't call this a solution to use before starting. Try a different combo of lens and distance to your subject. Also, recording in ProRes rather than raw can reduce the chances moire will appear.
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Troy Wuelfing

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 6:32 am

Dmitry Shijan wrote:RAW without OLPF is a pain.
You can try shift image X/Y position to 0.5 px. This removes Cross Hatching effect and and makes moire slightly less visible.
Also people calm that shootng ProRes downsampled in camera to HD or 2K produce very clear image.


unfortunately, we see this issue in every available codec, at every available resolution.
also our intent is to capture for UHD HDR mastering so shooting 2k would have been a non-starter anyway.

thanks for the great replies, still hoping blackmagic will someday see this issue as severe enough to warrant attention.
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Troy Wuelfing

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 6:38 am

Jamie LeJeune wrote:
Robert Niessner wrote:

I've salvaged shots using the same technique.

However, I wouldn't call this a solution to use before starting. Try a different combo of lens and distance to your subject. Also, recording in ProRes rather than raw can reduce the chances moire will appear.


hey, thanks for the tips, unfortunately moving the camera isn't an option, we have many many products (potentially thousands) that need filmed according to strict standards for consistency, and we have tested every codec at every resolution available and the result is the same.

we have tried every EF mount lens we have here, at various apertures, the result is the effectively the same.

we have ordered a PL mount for the camera and will try some zeiss glass we have, but I suspect it will not change the situation.

it seems as though the camera is not usable if you want textiles in your work, unless your willing to position the camera per the need to reduce moire rather than per creative or technical requirements.

we will continue testing on other textiles, but, we will likely test a red with interchangeable OLPF, alexa SXT, and alexa mini as replacements.
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Re: serious moire issues have halted production

PostWed Nov 22, 2017 7:38 am

Hey Troy,

I've been using the Cinema Camera for years, so I know all about the moire.
I came up with a solution using Fusion that I posted awhile back:

viewtopic.php?f=22&t=45371

It's quite a bit of post work, so I don't know if it's your solution, but I thought I'd pass it on.
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Troy Wuelfing

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 7:44 am

Mike C Bonner wrote:Hey Troy,

I've been using the Cinema Camera for years, so I know all about the moire.
I came up with a solution using Fusion that I posted awhile back:

viewtopic.php?f=22&t=45371

It's quite a bit of post work, so I don't know if it's your solution, but I thought I'd pass it on.


hey, I will check this out, but we have so many films to do that solving this in post, unless its super reliable and very automated isn't an option.
we strike our set 2-6 times a day and need to know we wont have an unrecoverable issue. if we wait until post to find out that we cant solve it we will be in big trouble.

thanks for the suggestions! if it works I will post back the results.
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Jamie LeJeune

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 8:03 am

Troy Wuelfing wrote:we have tried every EF mount lens we have here, at various apertures, the result is the effectively the same.

we have ordered a PL mount for the camera and will try some zeiss glass we have, but I suspect it will not change the situation.

it seems as though the camera is not usable if you want textiles in your work, unless your willing to position the camera per the need to reduce moire rather than per creative or technical requirements.

As has been noted, since the camera has no built in OLPF there will always be the chance that the right tiny repeating pattern at the right distance will exhibit moire. Sounds as if you're working right in that spot.

Have you tried adding different types of gentle diffusion filters to the front of the lens?
I've been meaning to test that myself to see if it could be a solution to pull out when needed, but moire hasn't really been an issue in my work with the 4.6K so I haven't gotten around to it.

I hope you find a solution that works for you!
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Troy Wuelfing

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 8:07 am

Jamie LeJeune wrote:[
Have you tried adding different types of gentle diffusion filters to the front of the lens?


we have not yet, but the idea of a super light pro mist came up, do you have a suggestion for something more appropriate? something that would create the diffusion, but not hurt the sharpness more than we could recover in a down sample from 4.6k to UHD?

thanks!
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Jamie LeJeune

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 9:00 am

Troy Wuelfing wrote:we have not yet, but the idea of a super light pro mist came up, do you have a suggestion for something more appropriate? something that would create the diffusion, but not hurt the sharpness more than we could recover in a down sample from 4.6k to UHD?

I haven't personally tested enough different types to make a recommendation.
This comparison video of a bunch of types of diffusion may help you choose:

I often use various levels of Hollywood Blackmagic filters on my interviews and then in post track windows on the eyes (much easier now thanks to Resolve 14) to add a few points of sharpening and make them pop again. I can get away with some pretty strong diffusion working that way.
So, you might test upping the diffusion level of the filter until the moire disappears (assuming that even works), and then see what it looks like with a bit of sharpening in post.
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Uli Plank

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 9:19 am

Get a Red. Seriously. I like BM cameras, but moiré will be an issue with sharp lenses.

Red went another route and got bashed in the early days like "it's so soft, that's not really 5K".

Even an older MX version will do, since you have controlled lighting.
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Robert Niessner

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 12:29 pm

I've experimented around with the DNG samples you've provided. Aliasing and moire are pretty bad. I could get rid of the color moire but the aliasing in the luminance is hardly removeable.

You will either need the Mosaic Engineering OLPF or get another camera - maybe a RED as Ulli suggested.
Last edited by Robert Niessner on Wed Nov 22, 2017 12:36 pm, edited 1 time in total.
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Troy Wuelfing

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 12:31 pm

Robert Niessner wrote:I've experimented around with the DNG samples you've provided. Aliasing and moire are pretty bad. I could get rid of the color moire but the aliasing in the luminance is hardly removeable.

You will either need the Mosaic Engineering OLPF or get another camera - maybe a RED as Ulli suggested.


yeah, unfortunately the mosaic engineering filter isn't shipping for a while.
we may try to rent a red camera with interchangeable OLPFs and see what we can do with that.
thanks for your effort, it is appreciated!
:D
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Robert Niessner

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 12:37 pm

This is the result I got with Photoninja:
Attachments
Moire_rem.jpg
Moire_rem.jpg (998.22 KiB) Viewed 1637 times
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Wayne Steven

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 2:07 pm

Without spreading the light of the pixels in the focus zone,
like an olpf does, but all over the image, you have little option at filming. Diffusion filtering will spread the light and sharpness. A milder diffusion filter might maintain the pixels original detail peaks in those pictures, but to counter the desaturation/contrast lowering of the spread of light you could lift colour/filter. But as I said before Red has better sensor in helium and a number of olpf.

Robert Niessner wrote:
Troy Wuelfing wrote:i can appreciate your situation of being able to move the camera a half step back to remove the moire.
we are filming a few thousand products with various textiles and things cant move or shift.
our subjects / heros are the textiles, and the camera is locked off and framing set.

it seems as though an OLPF should be created for this camera, the excuse of "shoot around it" is easy to say but not possible for our situation, a real solution which addresses the artifact issue would be preferred.

does anyone know why blackmagic doesnt make one?


It is VERY difficult and time consuming to make an OLPF fitting for a sensor. There is a reason why it takes Mosaic Engineering so long and why there is now a version 3 of the OLPF.
As Blackmagic cameras are designed for a great price/performance ratio there are certain things where they have to cut costs - and I think an OLPF is one of them.

However, I've successfully removed moire by using NeatVideo and its temporal filter combined with the spatial filtering of chroma only. This might work for you too.


I've identified this sort of thing as a fix years ago, from work of mine decades ago. It's amazing nobody develops it, but talking to people in the industry is like talking to block heads.
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Mike C Bonner

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Re: serious moire issues have halted production

PostWed Nov 22, 2017 5:35 pm

I had to take a crack at it. Here's what I came up with in Fusion:

A999_11211500_C001_000500-originalFusion.jpg
A999_11211500_C001_000500-originalFusion.jpg (924.2 KiB) Viewed 1549 times


But, yeah, this is a patch, not a solution.
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Robert Niessner

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Re: serious moire issues have halted production

PostThu Nov 23, 2017 12:44 am

Good job Mike!
Does Fusion have such a good Debayer?
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Mike C Bonner

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Re: serious moire issues have halted production

PostThu Nov 23, 2017 2:16 am

Ah, Robert, I wish it were that easy.
I posted a link to a previous thread above if you want to see the details.
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Robert Niessner

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Re: serious moire issues have halted production

PostThu Nov 23, 2017 2:37 am

Ah, ok. Had some hope for Fusion.
I already knew that moire removal technique.
I was hoping for something simpler here which could be automated.
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John Brawley

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Re: serious moire issues have halted production

PostThu Nov 23, 2017 2:38 am

The trend in imaging is towards NOT having OLPFs.

I shoot Leica S, Leica M-E, Olympus EM1 Mark 2 and NONE of them have OLPF's. NONE ! They in fact advertise the fact they don't have them as a feature. The X1 D From Hassy is the same. These are very high end cameras, about as much as you can spend on a still system.

Many cameras that have do have OLPFs still have issues. I got bitten on an F55 shoot with a shot that was rejected for broadcast.

Strangely I haven't ever been rejected on the many many UM Pro shots that are in my many hours of TV broadcast.

BUT

It's probably more to do with how I shoot. I use older (softer) lenses, I tend to shoot pretty shallow and longer focal lengths, all of which helps.

If you want wide shots of textiles, then the Ursa Mini Pro is probably the worst camera you could get.

RED can be better because they have higher resolution, which also tends to minimise it, and they DO have OLPFs, however, be careful. They advertise it as a feature, but it's kind of a compromise. They have different OLPF's for low light and one that's called "skin tone". That gives you a sense of how difficult it can be to optimise an OLPF for a given sensor.

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Uli Plank

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Re: serious moire issues have halted production

PostThu Nov 23, 2017 4:40 am

Troy Wuelfing wrote:we may try to rent a red camera with interchangeable OLPFs and see what we can do with that.


You don't need a recent Red with interchangeable OLPFs. All Red cameras had strong enough OLPFs from the start. The interchangeable ones exist for a totally different reason.

Yes, the trend is away from OLPFs, but only for cameras with extremely high resolution. When the sensor approaches the resolution limit of the lens, moiré is less of an issue. A 4.6K BM camera is already better than the 2.5K. On my Sony A7R II with 42 mpx I hardly ever see moiré in photography, but I like to use older lenses like Zeiss C/Y or Minolta SR. But with good glass on a 4.6K BM you are not yet close to the limit.
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Robert Niessner

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Re: serious moire issues have halted production

PostThu Nov 23, 2017 9:07 am

Uli, yeah and the old RED ONE MX had a really strong OLPF. Always had to add lot's of sharpening in post to get back the details.
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Wayne Steven

  • Posts: 375
  • Joined: Thu Aug 01, 2013 3:58 am

Re: serious moire issues have halted production

PostThu Nov 23, 2017 9:20 am

You want a helium camera, whatever resolution, because of better sensor picture (the olpf set is just good to test for fine tuning difficulties). Even though previous Dragon, and before I didn't like the leveling (the contrast of skin tones was a big one) and color as well. You could use a 6 year old Red, as long as you spent time lighting etc, to compensate for the sensor.

However, I see some of this issue on the 4.6k, and on the frabric of that fusion reprocessed shot above. I'm still waiting for mk2, seriously. It might be ok for a pocket like product, but if I'm going outlay bigger money, I want something more like the helium, that seems to fit human vision and gotten over some of these issues.

Lack of Olpf being a feature, is something for stills, not video cameras (a flip out olpf here would have been good). It is not like these cameras have nearly 100% fillfactor like a Sigma given chip, which would help a bit more, but still needs one (the olpf effectively gives an over 100% fill, getting rid of the issue).

Somebody try this. Get a speed booster, and try putting light diffusion filters behind it (even better behind a projected dof adaptor)? The image is being set by the adaptors, so afterwards the pixels are more formed. Their is a special filter that has a very narrow range of spread.
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Uli Plank

  • Posts: 1918
  • Joined: Fri Feb 08, 2013 2:48 am

Re: serious moire issues have halted production

PostThu Nov 23, 2017 2:19 pm

Well, a Helium is still a tad more expensive than the UMP46…
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Carlos Garcia-Diaz

  • Posts: 25
  • Joined: Mon Feb 01, 2016 9:40 pm

Re: serious moire issues have halted production

PostFri Nov 24, 2017 7:25 pm

Uli Plank wrote:Well, a Helium is still a tad more expensive than the UMP46…


Not as expensive as buying two cameras only to find out that they're not the right ones for the job after production has begun. Really, all you have to do is do a cursory search on these forums to see that moire and FPN are potential problems with these cameras.

viewtopic.php?f=2&t=57589&p=359894&hilit=Moire#p359894

As others have stated, get a Red. Not expensive if its right for the job.
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Denis Kazlowski

  • Posts: 51
  • Joined: Tue Nov 28, 2017 12:54 am
  • Location: NJ - USA

Re: serious moire issues have halted production

PostFri Dec 01, 2017 2:48 am

Troy Wuelfing wrote:
Jamie LeJeune wrote:[
Have you tried adding different types of gentle diffusion filters to the front of the lens?


we have not yet, but the idea of a super light pro mist came up, do you have a suggestion for something more appropriate? something that would create the diffusion, but not hurt the sharpness more than we could recover in a down sample from 4.6k to UHD?

thanks!


Are you able to test with a AJA CION? They went marketing crazy telling people how their "OLFP+IR can survive any fabric"
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robert Hart

  • Posts: 114
  • Joined: Mon Jul 28, 2014 3:16 pm

Re: serious moire issues have halted production

PostFri Dec 01, 2017 1:46 pm

Wayne. DOF or groundglass based adaptors hit a resolution wall at around 2K unless you are using something that projects onto a large format like medium format or plate camera like the coatwolf arrangement.
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Wayne Steven

  • Posts: 375
  • Joined: Thu Aug 01, 2013 3:58 am

Re: serious moire issues have halted production

PostSun Dec 03, 2017 7:49 am

Hi Robert. Hard to believe it couldn't be done better, the visible frequencies are below 1 micron, so that is 1000 a millimetre. Given X amount of increase in size (I'm not forgetting aberration this size multiplication should take care of it). Anyway, they have 1 micron pixels, even 50nm pixel technology in the cinema sensor brand, these days. So, a projection of 4/3rds or more should be possible. If it would be just the resolution of 2k, it would still be about the shift across the matrix, which for many should be continuous. So, even the 2k resolution, each fine grade position would be 2k, resulting in a very diffused 4k pickup (probably not very useful at 4k or 8k). But this is what they want. Low pass filters can be spread 16 pixels wide. This could be extracted and cleaned up, but the industry hasn't been up to it.

But as you say, use a bigger format for dof. I would have thought a lens for the larger medium format would have been better and created a better feel, anyway. A condenser dof adaptor for that would be good. Anyway, fantastic should be happy (recognised the materials) .

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