What to do against moiree?

[redfalo]

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Today for the first time I have some moiree problems. Shot taken with M8 (latest FW), Cron 50 with IR cut filter, ISO 320 and indirect flash. DNG, processed in LR.

[ATTACH]77783[/ATTACH]

 

On his right shoulder there is are heavy moiree effects.

[ATTACH]77784[/ATTACH]

 

Does anyone have a clue what to do against this (apart from manually correcting it in PS?)

 

No moiree effect on the shots taken without flash, BTW.

Thanks

Olaf

[wparsonsgisnet]

I find it interesting that there is no moire without the flash. From the lack of shadows, it appears that you were using either bounce or an umbrella. I would not have expected to see the problem from diffuse lighting.

 

I believe the previous postings about this suggested correcting with add-in's, as you indicate.

 

If you do a search, there were several add-in's suggested.

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[Guest WPalank]

Olaf,

This issue was pretty much discussed to death in this thread:

Unreal City

 

Here's how I got rid of the color information:

The other method for removing the color element of the moire in PS and stay in RGB is to duplicate the layer, apply a Gausian Blur until the color noise disappears (in this case 7 and yes the photo looks REALLY blurry). Change the blending mode of this copy layer to Color. If you get color shifts globally (I did in this image especially the blues), Option click the new layer mask icon to create an adjustment layer and turn it black and then paint with white on the layer mask where you need to remove the moire. I got the following result.

[Guest WPalank]

You can also go into the Lab Color-space where I got this result. I was working only on the camera left side.

[Guest rweisz]

 

Does anyone have a clue what to do against this (apart from manually correcting it in PS?)

 

 

Er, use a Canon? I've never used my M8 with flash, maybe that's why I've never gotten it. I wouldn't want to have to go through 500 shots correcting it in PS. Moiree is a PITA. Come to think of it, so is my brother Morrie.

[redfalo]

Thanks for the links, I´m going to read through them tomorrow.

I understand I can get rid of the color effects. I there any possibility to get rid of the weird structures, too?

 

I find it interesting that there is no moire without the flash. From the lack of shadows, it appears that you were using either bounce or an umbrella. I would not have expected to see the problem from diffuse lighting.

 

I used some kind of a makeshift bounce: A Nikon Speedlight SB-15 (the final relict of my SLR stuff), turned against the ceiling (90 degrees).

 

Maybe the moiree is not due to the flash but to the higher f-stop and sharpness with flash? Shots without flash were done at f=2.0, with little depth of field. Shots with flash were done at f=5,6.

 

Thanks again

Yours

Olaf

[ChrisC]

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Olaf - Another option. About 20-30 seconds work:

 

In Photoshop; duplicate layer [blending mode NORMAL]. Take an accurate colour sample [from an unaffected area of material] with the Eyedropper Tool. Select BRUSH tool and set it's blend option to COLOUR . Paint the moire discolouration away [@ 100%]. In this case I needed two colour samples because [presumably] areas of the clothing had different mixes of ambient/flash colour temperature effects. Paint and watch; if the colour of the painting is inaccurate - simply undue, resample, and paint again.Easy peasy in this instance.

 

.................. Chris

 

 

EDIT....... DAMN. Wasted my time again......... I've only just seen your comment about not wanting a Photoshop solution.................. suppose I could put the discolouration back if you want me to.

[adan]

Carry along a jacket with a pattern you know is moire-resistant - and have your subject wear it for the photos (you know, like Nat. Geo. photographers used to carry along a red shirt for folks to wear in landscape shots?). In this case it might have been an improvement even if there WERE no moire issues.

 

8^)

 

Seriously: Your hand-held shots without flash likely blurred the image just enough - through longer exposures or wider apertures - to act as an anti-alias filter.

 

Also - if you moved in a little closer or back a little further - it may have changed the "frequency" of the cloth texture relative to the pixels just enough to eliminate the moire.

 

Might try shooting DNG + JPEG if moire looks likely - JPEG mode supposedly kicks in an electronic anti-moire filtering (a la the DMR) as well as a touch of noise reduction that may also kill some of the moire effects.

[redfalo]

Originally I wanted to go to bed at least one hour ago... But I did some more experiments. I found the method described by William working amazingly good. To avoid that parts of the picture which have no moiree are affected by the gausian blur filter (the right hand in his picture for example) I did work only on selected areas of the picture.

[ATTACH]77833[/ATTACH]

@ Chris: thank you anyway. I tried it but right now I think the gausian blur method is more convenient.

 

Interestingly the whole thing seems to be a problem of LR in the first place. Driven by curiosity I developed the DNG shot in C1 (3.7.6) as well. I usually do not use C1 anymore since LR seems more capable and convenient. But C1 copes much better with the moiree, as one can clearly see:

[ATTACH]77832[/ATTACH]

Yours Olaf

[ChrisC]

...... C1 copes much better with the moiree,.....

 

Olaf - William's Gaussian Blur, layer mask process is very good I agree. But I am amazed by the difference that C1 processing gave. Maybe this has come up before, but I have no recollection if it has [my memory is fairly lousy though]. I'd be interested in an explanation of why the two processes are so different, can anyone elaborate?

 

................... Chris

[Artichoke]

Olaf - William's Gaussian Blur, layer mask process is very good I agree. But I am amazed by the difference that C1 processing gave. Maybe this has come up before, but I have no recollection if it has [my memory is fairly lousy though]. I'd be interested in an explanation of why the two processes are so different, can anyone elaborate?

 

................... Chris

Phase One helped Leica with the design of the M8 & C1 comes bundled with the camera

it should come as no surprise that C1 does best with the M8's raw files

I have never seen artifacts such as you posted with files processed with C1

once you get the hang of it, it is a fairly simple to use raw processor

[robertwright]

fyi the in camera jpeg won't help you in this situation, it will have moire too. It is simply the lack of AA filter and being at a particular distance to the fabric and having sharp focus on the jacket. It can happen at any aperture and regardless of flash or not. I have many examples, trust me...

 

C1 has a photoshop anti-moire plugin that is good for this, unfortunately it is not updated for CS3 or leopard.