Moire patterns

[hmarkweidman]

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I have about 6,000± frames on my Leica SL, which I love. I knew that there was a chance of moire patterns with the SL, since there is no anti-alias filter. I recently photographed a musical performance and for the first time experienced moire patterns. If you look closely at the attached JPEGs you will see a moire pattern in the woman’s shirt (attached images are full frame & cropped area in question). There are some good Photoshop techniques to remove the moire patterns, though it does take some time.  I thought this might be of interest to the group.   Mark Weidman

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[mmradman]

Joy of 24Mp sensor, you are not the first to notice it.

 

Mitigation:-

Higher MP sensor, maybe next iteration of SL601.

Image slightly out of focus.

Film.

[hmarkweidman]

Thanks for your response.  I am not so sure a larger sensor would prevent the problem.  I think it is more a function of not using an anti-aliasing filter.  A larger, more sensitive sensor may in fact exacerbate the problem.  Interestingly enough, I have at least 25,000 captures with a Leica M9-P, which also does not have an anti-aliasing filter.  And, I have never had any moire pattern problems with that camera.  This could just be simple chance as I had maybe twenty or more frames of the female singer in my example and the moire patterns appeared only when she, and her shirt, were at precisely the right (or wrong!) angle to the sun.

[mmradman]

You were lucky with selection of subjects with you M9, it is there.

[mjh]

Occasional moiré is the price you pay for the increased resolution you get from a sensor without a low-pass filter. Thankfully moiré is easy to get rid of in Lightroom (or ACR).

[jaapv]

Not always that easy, Michael. Try photographing a JU 52 with an M8

[jaapv]

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Thanks for your response.  I am not so sure a larger sensor would prevent the problem.  I think it is more a function of not using an anti-aliasing filter.  A larger, more sensitive sensor may in fact exacerbate the problem.  Interestingly enough, I have at least 25,000 captures with a Leica M9-P, which also does not have an anti-aliasing filter.  And, I have never had any moire pattern problems with that camera.  This could just be simple chance as I had maybe twenty or more frames of the female singer in my example and the moire patterns appeared only when she, and her shirt, were at precisely the right (or wrong!) angle to the sun.

As this is a resonance-type of aberration, the problem will get less with higher MP counts. Not sensor size, but pixel density.

[hmarkweidman]

Occasional moiré is the price you pay for the increased resolution you get from a sensor without a low-pass filter. Thankfully moiré is easy to get rid of in Lightroom (or ACR).

 

I would love to know your method for removing moire patterns in Adobe Camera Raw.  In Photoshop I created a duplicate layer of the background, changed the blending mode to Color, assigned the light blue color of the shirt, then using the Brush tool I brushed over all the pink stripes, which were then removed nicely.  I did not know there is a method in ACR.  Thanks.   Mark Weidman

[hmarkweidman]

Not always that easy, Michael. Try photographing a JU 52 with an M8

What the heck is a "JU 52"?

[jaapv]

Tante Ju.

A German trimotor transport plane, built by Junkers, one could call it the German answer to the Dakota.

It was made from  corrugated light metal. If you try to photograph it with an AA-filterless camera, the parts of the fuselage in the plane of focus will show horrible geometric moirë effects.

 

 

https://en.wikipedia.org/wiki/Junkers_Ju_52

 

 

My point was that it is indeed easy to get rid of the colour-aliasing part of moirë, but virtually impossible to fix the geometric pattern distortions.

[scott kirkpatrick]

I get Moire when photographing buildings that have window screens, railings with closely spaced uprights, or other repetitive structures. Leica's lenses reproduce this detail down to sub-pixel levels (6 microns for the SL, 4+ microns for the CL).  Think of it as a strength to be managed appropriately.

 

The JU52 corrugated skin is quite handsome, BTW.  Lufthansa keeps a few of them around to show off, and there is luggage designed to carry that look.

Edited July 20, 2018 by scott kirkpatrick

[jaapv]

With window slates one can at least hope to restore the pattern through cloning. The JU 52 is rounded so the corrugations distort in all directions in the plane of focus.

[frame-it]

which lens did you use ?

I have about 6,000± frames on my Leica SL, which I love. I knew that there was a chance of moire patterns with the SL, since there is no anti-alias filter. I recently photographed a musical performance and for the first time experienced moire patterns. If you look closely at the attached JPEGs you will see a moire pattern in the woman’s shirt (attached images are full frame & cropped area in question). There are some good Photoshop techniques to remove the moire patterns, though it does take some time.  I thought this might be of interest to the group.   Mark Weidman

[hmarkweidman]

which lens did you use ?

 

Photos shot on SL with 90-280mm lens at 124mm at f/5.6 1/2000 sec.

[Steve McGarrett]

I very much prefer some Moiré pattern in some picture and better resolution and micro-contrast in all the others, than the opposite.

But of course YMMV...

 

BTW, even with the AA filter, a lens can excite Moiré, if it's good enough (like many Leica ones are)

Edited July 20, 2018 by Steve McGarrett

[mjh]

I would love to know your method for removing moire patterns in Adobe Camera Raw.  In Photoshop I created a duplicate layer of the background, changed the blending mode to Color, assigned the light blue color of the shirt, then using the Brush tool I brushed over all the pink stripes, which were then removed nicely.  I did not know there is a method in ACR.

With Camera Raw you can use the brush to remove moiré wherever it shows up.

[mjh]

Not always that easy, Michael. Try photographing a JU 52 with an M8

A Ju 52 isn’t that much of a challenge; what’s really difficult is a case where there is no repeating pattern but just a singular dark line against a bright background.

[jaapv]

I'll have to look up my old attempts with the M8; I had to junk a number of shots

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Hallo,

Look here: Leica L-Mount

[hmarkweidman]

With Camera Raw you can use the brush to remove moiré wherever it shows up.

 

Thanks for the tip, I had never noticed that option with the brush in ACR & will give it a try.   Mark Weidman

[robgo2]

I would love to know your method for removing moire patterns in Adobe Camera Raw.  In Photoshop I created a duplicate layer of the background, changed the blending mode to Color, assigned the light blue color of the shirt, then using the Brush tool I brushed over all the pink stripes, which were then removed nicely.  I did not know there is a method in ACR.  Thanks.   Mark Weidman

 

For those who use On1 Photo RAW, you can do essentially the same thing with a Local Adjustment brush > Paint with color. Simply select the light blue color of the shirt, and paint. The Replace Color Mode gives more effective and realistic results.