Moire

[narikin]

There's a particular building I've been photographing recently, but they've refurbished it with grills below the windows that give me a lot of Moire in each and every image. image

Any answers? I know how to remove color moire from images in PS, but L Moire is there too, and very difficult to get rid off without weirdness.

I'm hoping the upcoming IQ4 with a higher frequency/ smaller pixel pitch will fix this.

[Bart_van_der_Wolf]

There's a particular building I've been photographing recently, but they've refurbished it with grills below the windows that give me a lot of Moire in each and every image. image

Any answers? I know how to remove color moire from images in PS, but L Moire is there too, and very difficult to get rid off without weirdness.

Hi,

Have you tried Capture One (instead of Photoshop ACR)?

At shooting time of architecture, I try to take an additional shot with a narrow enough aperture to let diffraction kill any possibility of moiré occurring. That shot can be used in a layer to locally hide moiré. The required aperture depends on the sensor pitch and whether or not an Optical Low-Pass Filter (OLPF, or AA-filter) is used.

As a guideline, N = 1 / (cycles_per_mm * lambda), with both cycles/mm and wavelength lambda expressed in millimeters, gives the aperture where diffraction will drive the MTF from a circular aperture lens to zero.

I'm hoping the upcoming IQ4 with a higher frequency/ smaller pixel pitch will fix this.

A smaller pitch will help, but it may or may not be enough.

Cheers,
Bart

[MichaelEzra]

You may have to do dodge and burn by hand.
To minimize the L moire, use HSV adjustments and brighten the blue, cyan and yellow a bit.

[Bart_van_der_Wolf]

A New Way to Remove Moire

Cheers,
Bart

[narikin]

Thanks both of you.

Bart - good suggestion about doing another exposure at another aperture. seems like an answer if you are on a tripod, but these are handheld. Might have to change my technique.

and the video link to removing moire - yes I know that one, and have used it, for me it still doesn't always work perfectly on L Moire, but it's a great technique. Amazing what people figure out!

[smahn]

Amazing what people figure out!

Along those lines, you'd have to refine this as I just made it up. See if this effect would be in the ballpark of acceptable.

Dupe the layer, convert to smart object for further explorations and refinement of blur radius (I happened upon 1.9 for this), blur, invert, mask, reduce opacity to 50%.

The basic logic is as follows: by blurring the area you turn the moire into luminosity blobs that upon inverting counter those present. You might do similar with luminosity masking and curves, I suppose.

Anyway, I spent more time writing this up than I did playing with the technique, so give it a whirl and see if you can refine it.

[alan_b]

Just another point of reference, from a shot today. 

Here's a full frame from a Nikon D810 w/ 19mm PC-E at f/8.  You can see moire in the grilles on the far wall even in this 1200px version.  Insets are 100% at f/8, 11, 16.  That's how I usually deal with it: shoot another frame stopped down, but I'm always on a tripod.

[StoryinPictures]

Great thread with some helpful tips. Thank you!

A New Way to Remove Moire

Interesting method. Too bad he never did the advanced video he mentioned but I am glad to have seen this one.

[Chris Barrett]

Wow... I get a bit of Moire with my Sonys but nothing that bad!  C1 pro has really good Moire correction and you can do it on an adjustment layer now 

[Bart_van_der_Wolf]

Great thread with some helpful tips. Thank you!

Interesting method. Too bad he never did the advanced video he mentioned but I am glad to have seen this one.

Yes. There are multiple ways of addressing this type of issue. Best is to prevent it though (and Capture One Pro is good at minimizing it if it's in the Raw capture), because aliasing will create larger 'detail' than what caused it and that might make it difficult to remove after the fact.

An inverted High Pass filtered layer in Luminosity Blend mode can also help, if need be.

Cheers,
Bart

[narikin]

Wow... I get a bit of Moire with my Sonys but nothing that bad!  C1 pro has really good Moire correction and you can do it on an adjustment layer now 

Yep, use that layered on C1, helpful, but not as powerful as some of the techniques suggested here, which you need to really correct L moire.

I'm always amazed that people say they don't get moire/ never see it. Michael Reichman (RIP) used to say it was a non issue for him with Phase backs! For organic shooters - landscape rocks and trees, or course it's not an issue, but anyone working in a built environment, or with people wearing texture clothes, will find it, especially in bright light.  I work in a city, and get it every single day I work. Perhaps I should get a less sharp lens?

[narikin]

Along those lines, you'd have to refine this as I just made it up. See if this effect would be in the ballpark of acceptable.

Dupe the layer, convert to smart object for further explorations and refinement of blur radius (I happened upon 1.9 for this), blur, invert, mask, reduce opacity to 50%.

The basic logic is as follows: by blurring the area you turn the moire into luminosity blobs that upon inverting counter those present. You might do similar with luminosity masking and curves, I suppose.

Anyway, I spent more time writing this up than I did playing with the technique, so give it a whirl and see if you can refine it.

Just to check I understand this right:

Create new background layer > smart object > *Gaussian* blur smart filter > Invert... (the whole background copy layer?) > apply layer mask hide all >reduce layer opacity to 50% > paint mask (white brush) in Moire areas to remove.

Thanks
 

[smahn]

Just to check I understand this right:

Create new background layer > smart object > *Gaussian* blur smart filter > Invert... (the whole background copy layer?) > apply layer mask hide all >reduce layer opacity to 50% > paint mask (white brush) in Moire areas to remove.

Thanks

Yup. See my layers in the pic I posted. Lemme know if your results don't match mine.

And for the mask you might find the pen tool or the polygonal lasso best for those straight lines and getting in the corners.