BMPCC: strong moire - lens too sharp?

Hi,

I'm using the Sigma 18-35 (with and without Speedbooster) a lot and get almost amazing results. Even though it is very sharp at 1.8, stopped down it seems to become "too" sharp for the BMPCC. What I get is moire, moire, moire...
Using ND's is not always suitable.

Is there any filter to put inbetween lens and body or does someone know a proper solution in postproduction to reduce/eliminate the moire?

Cheers

Alex

Mosaic Engineering were working on an optical low pass filter for the BMCC. Not sure what the status is on that. Don't think there are any out there for the BMPCC.

You could try using a Black ProMist or MovieMist filter. It'll soften the image a little and reduce the effect.

In post you can try blurring the chroma channel. This will make it less distracting.

Hi Adam, thanks for your quick reply!

I'll give the color channel blurring a try.

Hollywood Black Magic filter. Keep it on ever digital camera, watch talent and make up start to really love you!


Another fun thing one could play with which was much more envogue a few years ago were front and or rear mounted nets; Janusz Kaminski is quite fond of them and they certainly make for an interesting look.

Please take a look at these images. Are the blue and pink blotches typical of the BMPCC? My previous cameras were also prone to moiré, but the Pocket Camera is by far the most effective moiré producing machine I´ve ever seen... There is maybe one RAW clip out of 10 which is mostly free of rainbow colors.
I don´t know how to avoid them when shooting vegetation.

Maybe my BMPCC needs to be checked by the guys at BMD?


Look at the branchwood and the water.

The treetops...

How are you processing your RAW files? What's the workflow?

How are you processing your RAW files? What's the workflow?

I always import my RAW files as sequence into After Effects, after making some adjustments in Camera Raw.
Sharpening is set to 10, only minor color correction is made, as I like to grade the footage inside AE.

Davinci Resolve doesn´t make any difference in terms of moiré.

My lens is a Sigma 18-35, boosted by the Metabones BMPCC adapter, tamed by a Heliopan Vario ND which is protected by a Haida UV/IR cut filter. I didn´t try shooting outside without the ND filter, but I don´t suspect the filter to cause or amplify any artifacts.

I know, softening the image (defocussing while shooting) can help, but soft vegetation doesn´t look good on the screen. Trees look like green cotton wool then. On the downside, keeping everything nice and sharp makes them look like Christmas trees, thanks to the absence of a proper OLPF.

As the famous image below shows a similar amount of blue and purple blotches, I guess my BMPCC behaves just like any other BM camera. I didn´t notice how overwhelming aliasing and moiré can be on this camera, until I went into the deep forest to capture some untouched nature.

This is apparently normal and it sucks. I had the same problem with the BMCC.

Just wait until you start filming people wearing clothing with patterns

Love the BMPCC but this is a major issue.

Chroma blurring helps.. but it doesn't remove it completely.. especially when it's very strong. I never had an issue with Moire until this one time someone wore a finely detailed blazer (thought to myself I'll fix it in post). Didn't think it was such a big problem, until I brought it into my computer to edit!

You'll have to probably use a lens filter to soften it up. And use good ol'ENG technique of avoiding certain patterns, and clothing..

BMD cameras don't use optical low pass filters like most other cameras do, thus you get sharper images, but also more moiré. It's never been a problem for me, until i got my speedbooster...

The 4k camera handles this issue way better. I see it in about 5% of my footage where with the BMCC it seemed to be in about 95% of my footage.

BMD cameras don't use optical low pass filters like most other cameras do, thus you get sharper images, but also more moiré. It's never been a problem for me, until i got my speedbooster...

Did the speedbooster amplify those artifacts, because of increased sharpness?
I´m used to avoid certain fabrics and grid patterns, because my GH3 isn´t free from moiré either, but the BMPCC is much worse. It´s funny and tragic at the same time that this camera is either black or white, at least for me. It does some things very well and others very bad. The dynamic range is wow, but so are the artifacts. RAW is wow, but so are hot (white) pixels that appear all over underexposed areas, as the camera gets warmer while shooting.

I´m not happy about ugly artifacts, but in consideration of the price, the BMPCC is still more satisfying than frustrating. Let´s see if I can reduce moiré by shooting with the lens wide open, which will soften the image a bit...

Thanks for your suggestions!

With 2400 x 1350 RAW resolution you should be able to get quite good results at 1200 x 725 resolution. That's almost, but not quite 1280x720.

The solution...Vintage lens..

There is an option in Resolve: Chroma Noise Reduction. It almost kills it. Tweak as needed and it should help a lot.

Motion Effects tab > Spatial NR > Chroma Threshold. Unlink the Luma Threshold otherwise your image will get too smooth.

Neat Video in AE does a good job.
Removing the blue and purple blotches has opened my eyes... The BMPCC produces artifacts in almost every part of the image!! It´s not really visible in darker areas, but the bright and contrasty parts are infested with artifacts! Small stones, branchwood, water, leaves, trees, hair... I regret having invested in accessories for this camera. I knew that I would have to deal with moiré, but I wasn´t prepared for rainbow land! Turning Neat Video on and off is like switching between heaven and hell.

Before and after Neat Video (200% crop):

A lot of those look like color fringes that you get from lenses that aren't apochromatic. Look at achromatic vs apochrmatic refracting telescopes to get some good examples - achromats tend to give you similar color fringes when looking at bright objects.

I haven't seen any flaws that glaring in my footage so far.

A lot of those look like color fringes that you get from lenses that aren't apochromatic

I don´t think these are color fringes that can be related to my lens.
The blue and purple blotches do also appear in properly exposed footage, but seem to be reduced in ProRes mode. It´s much worse in RAW mode, maybe because ProRes is a little bit softer, I don´t know.

As the artifacts keep their characteristics, no matter which lens I use, the camera must be the source of error.

Can you share a DNG?

I'm wondering if it's being made worse by how the DNG is being processed in After Effects.

Here is the DNG file. Maybe I´m the error source, but I highly doubt it.

https://www.dropbox.com/s/cs4xe9r2qbfljlr/Blackmagic%20Pocket%20Cinema%20Camera_1_2014-04-30_1642_C0001_000459.dng

I'll have a look later this evening when I'm back at my edit suite.

Can you share you Adobe CameraRAW settings? (You can save it as a preset from the ACR interface).

I'm not saying there is no aliasing issues, just that yours seem way more exaggerated than I've seen in my footage.

That's quite a difficult shot to get, even with 13 stops of dynamic range, no ND filter on this shot? I think even a polariser filter may have helped even out the strong highlights for this shot?

I'll have a look later this evening when I'm back at my edit suite.

Can you share you Adobe CameraRAW settings? (You can save it as a preset from the ACR interface).

Here is the .xmp file for Adobe Camera Raw. I don´t know the original settings anymore, but for this test I only added some sharpness, some saturation and made minor highlights/shadows adjustments.
https://www.dropbox.com/s/oubfksvfrmtsyea/bmpcc_test.xmp

I know that this camera isn´t free of aliasing, but there are many shots where I can see blue/purple blotches between the branches of distant trees, although there should be nothing but some white or blue from the sky in the background.


Why are some treetops decorated with blue spots, although I can´t see complex patterns here? Some trees have it, some not. This is a snapshot from Adobe Camera Raw with +15 sharpening, +5 saturation and some exposure correction. Nothing else.

Maybe I´m just to inexperienced to know how to work around this. My camera experience is limited to GH2 and GH3. ETTR is new to me, as is shooting RAW in 1920x1080.
It´s actually a strange thought, but could my Heliopan Vario ND amplify these artifacts?
According to a fader ND shootout from Frank Glencairn, the Heliopan ND can produce some sort of moiré...
http://frankglencairn.wordpress.com/2012/12/08/nd-fader-shootout-heliopan-vs-the-new-genus-eclipse/

Here is the DNG file. Maybe I´m the error source, but I highly doubt it.

I don't believe you are at fault at all.

Here is your still processed via RawTherapee (where you can control the de-Bayering process far better than anything else I know of).

ps: the uploaded file also shows all of your image (1944 × 1104 pixels).

Blackmagic Pocket Cinema Camera_1_2014-04-30_1642_C0001_000459-1.jpg (733.9 KiB) Viewed 17466 times

That is a very difficult shot for most cameras.

ACR_test.jpg (781.68 KiB) Viewed 17443 times

Not sure if my ACR version is as bad as yours. Uploaded for you to look at.
Just a note. I see from your setting file you are using the 2012 process. When using ACR with CinemaDNGs its advisable to use the 2010 process rather than the 2012 process. It seem that the 2012 process is more suited to stills and does a lot of the calculations specifically for each frame. This can cause flicker.

Resolve_test_1.1.1.jpg (707.77 KiB) Viewed 17443 times

I was able to get a much cleaner image in Resolve.


Remember that unlike DSLRs and many video camera, the BM cameras do not image processing in camera. Add to that the fact that there is no Low Pass filter. So you really need to do a little noise reduction in post.

I was able to get a much cleaner image in Resolve.

Thank you very much! Which settings did you use in Resolve to get such a nice looking image?

I was able to get a much cleaner image in Resolve.

Thank you very much! Which settings did you use in Resolve to get such a nice looking image?

RAW was processed as BMFilm, adjusted the colour balance to taste.
Node 1: Colour balance, Lift, Gamma, Gain adjustment and Chrome noise reduction - could split this over 3 nodes if you like more control
Node 2: Slight Sharpen
Node 3: LUT (beta version of a LUT CaptainHook is working on, you can use his current BMFilm LUT)

DRX file:

Resolve_test_1.1.1.drx.zip

(150.21 KiB) Downloaded 272 times

I appreciate your help. In conclusion, my BMPCC footage looks "normal" in terms of aliasing, right? If this is what any BMPCC image would look like in these circumstances, I only have to handle the camera right and treat those DNG files good...

I can find chroma noise reduction in the motion effects tab? I can´t make any adjustments there, all options (spatial NR, temporal NR, motion blur) seem to be locked. I´m working with Resolve 10 Light.
Actually I´m not really working, as I´m not very familiar with resolve yet.

I appreciate your help. In conclusion, my BMPCC footage looks "normal" in terms of aliasing, right? If this is what any BMPCC image would look like in these circumstances, I only have to handle the camera right and treat those DNG files good...

Yeah... the footage looks normal. Just need a little love in post.

I can find chroma noise reduction in the motion effects tab? I can´t make any adjustments there, all options (spatial NR, temporal NR, motion blur) seem to be locked. I´m working with Resolve 10 Light.
Actually I´m not really working, as I´m not very familiar with resolve yet.

Noise reduction is only available in the full versions.

In the Lite version you could try blurring the chroma channel. I'll create an example and upload the DRX file.

Just noticed I uploaded the wrong DRX file. Have updated my post above.

Here you go. A zip file with both Resolve and Resolve Lite version of the fix.

Includes your sample image with and without the "fix" so you can compare them.

Too big for the forum upload so it on my DropBox:
https://dl.dropboxusercontent.com/u/646 ... %20R10.zip

Thank you very much!

Nice one, Adam

Great job Adam!

Wich solution do you prefer, blurring the chroma channel or using the Chroma Noise Reduction?

I have a BMCC and am "addicted" to Chroma Noise Reduction, seems every image looks better with it, even skintones.

Great job Adam!

Thanks

Wich solution do you prefer, blurring the chroma channel or using the Chroma Noise Reduction?

I have a BMCC and am "addicted" to Chroma Noise Reduction, seems every image looks better with it, even skintones.

When I was running R9 I used the blur method used in the Lite example. Now with the new updated NR tools in R10 I prefer the Chroma Noise Reduction method. It's much quicker to do and I fee you have more control.

Both give very similar results, as seen in the examples in the zip file.

Great job Adam!

Thanks

Wich solution do you prefer, blurring the chroma channel or using the Chroma Noise Reduction?

I have a BMCC and am "addicted" to Chroma Noise Reduction, seems every image looks better with it, even skintones.

When I was running R9 I used the blur method used in the Lite example. Now with the new updated NR tools in R10 I prefer the Chroma Noise Reduction method. It's much quicker to do and I fee you have more control.

Both give very similar results, as seen in the examples in the zip file.

Thanks!

I believe it has more to do with the lens than the camera.
When i shot with my Tokina 11-16 i would get a lot of purple/green fringing, wich is what's happening with the tree footage (i think that aliasing is different from fringing).
Shooting a city landscape at noon was terrible but if i use my Zeiss glass i don't see it.

Adam, your preset works miracles! I´ve tried it with some aliasing polluted footage and the ugly color blotsches seem to be gone...

You just made my day!

Is there a preset sticky? Might be a good idea.

Adam, your preset works miracles! I´ve tried it with some aliasing polluted footage and the ugly color blotsches seem to be gone...

You just made my day!

No problem. Glad I could help.

I can't take all the credit for it tho as it's based on a tecnique shared by Paul Del Vecchio over a year ago.