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Archive 2017 · Does anyone know how...

  
 
Bob Jarman
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p.1 #1 · p.1 #1 · Does anyone know how...


to deal with what I guess in moire?

Patterns vary with size of image...

Bob

Curiously when I click the mouse on the image in LR moire appears.

Larger export - an artifact of display?

I guess one quick answer is do not photograph picket fences












50%







33%







zoom in viewer triggers moire




Oct 15, 2017 at 02:58 PM
ben egbert
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p.1 #2 · p.1 #2 · Does anyone know how...


Yep it's moire. Now I have said all I know about it. I bet kent has some ideas.


Oct 15, 2017 at 04:34 PM
Rick Joyce
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p.1 #3 · p.1 #3 · Does anyone know how...


This article may help

http://unsharp-mask.blogspot.ca/2007/08/moir-removal-in-photoshop.htm




Oct 15, 2017 at 05:45 PM
Bob Jarman
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p.1 #4 · p.1 #4 · Does anyone know how...


Rick Joyce wrote:
This article may help

http://unsharp-mask.blogspot.ca/2007/08/moir-removal-in-photoshop.htm




Thanks Rick,

Apparently not a solution for this matter, both a and b channels are gray in LAB - mono image. Problem appears in L channel only (at least what I think).

Bob



Oct 15, 2017 at 07:00 PM
RustyBug
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p.1 #5 · p.1 #5 · Does anyone know how...


Bob Jarman wrote:
when I click the mouse on the image in LR moire appears.


Don't click the mouse ... problem solved.



A couple things come to mind.

1) Looking at the different zoom levels, it renders different amounts of moire'. I have noticed this before on many different things, but as long as I'm good at 100%, I don't think much about it. I've resized images up / down and seen the moire' come & go accordingly.

2) Are you letting LR do sharpening on your view/preview? Again, I think this is being artificially display induced, as the 100% version only has one section of fence (the angled one) that hints at moire'.

Generally speaking, moire' is a frequency issue. By scaling things down, you are changing the frequency. If you want to scale down, you might need to apply some form of blur / NR / etc. prior to scaling down. Conversely, you might try to uprezz the image and see how the different algorithm (bicubic, linear, etc.) might play to adjust the frequency.

However, if this is just your "viewing" and not your final output, likely nothing to be concerned with. I'd run a test print from a section @ 100%, and see if it shows up in print. Depending on your workflow, you may want to modify your sharpening algorithm, as a "softer" transition may be less susceptible to the frequency relationship. Also, if LR is applying output sharpening, that might be something to consider adjusting in your workflow as well.

Is the 100% view sooc / raw, or is it somewhere along the path of PP (i.e. did you have any sharpening applied by LR or on the way in? Personally, I have all my input set to "0" in ACR or DPP when bringing things into PS.

Hard to say from here, but I suspect that the "near" (i.e. not really) moire frequency territory of the fence is being induced into moire' territory by either scaling or sharpening or a combination of both.


Here's your large view reduced to 50%. I blurred it some before downrezzing it (reduced contrast a bit, and brightened it some, too). THEN applied some sharpening (which drives contrast darker / lighter to recover the blur / contrast reduction). Depending on how much sharpening I applied, I could certainly induce MORE MOIRE' (exaggerated examples for ease of view) ... so, here again, I think your workflow / usm might warrant some modification for the structure that the fence represents. Might even consider some masked / selective sharpening for the differently structured areas in the scene.

Best to work from RAW, but hopefully you get the gist that our processing can induce moire' that didn't originate from the actual capture. Thus we may need to modify our usual processes to safeguard against inducing the moire'.

HTH ... but, I really think this one is more of a viewing issue on your display in concert with USM or LR sharpening in your previews (i.e. you don't have a real issue, just the illusion of one).













Oct 15, 2017 at 08:59 PM
AuntiPode
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p.1 #6 · p.1 #6 · Does anyone know how...


When the grid of a fence makes your eyes take offense, that's a moiré.

<ducking>



Oct 16, 2017 at 12:12 AM
Bob Jarman
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p.1 #7 · p.1 #7 · Does anyone know how...


RustyBug wrote:
Don't click the mouse ... problem solved.

A couple things come to mind.

1) Looking at the different zoom levels, it renders different amounts of moire'. I have noticed this before on many different things, but as long as I'm good at 100%, I don't think much about it. I've resized images up / down and seen the moire' come & go accordingly.

2) Are you letting LR do sharpening on your view/preview? Again, I think this is being artificially display induced, as the 100% version only has one section of fence (the angled one) that hints at moire'.

Generally speaking, moire'
...Show more

---------------------------------------------

AuntiPode wrote:
When the grid of a fence makes your eyes take offense, that's a moiré.

<ducking>



Thanks Kent,

A friend in Oz, across the water from Karen, also told me the anomaly is display/size related, no problem at 100% so not really moire. I'll explore more, maybe a bit OCD? , later.

Karen, you owe me for setting that one up for you - nicely played

Bob



Oct 16, 2017 at 07:14 AM
AuntiPode
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p.1 #8 · p.1 #8 · Does anyone know how...


Actually, there are two opportunities for moiré - the worst is sensor interaction moiré where the grid pattern of the sensor interacts with a pattern in the subject. It's worse because the image formed will contain the moiré pattern and any faithful print or display will show the moiré pattern, regardless of magnification. Many camera sensors are covered with a plate that slightly diffuses the light to reduce sensor pattern moiré. The other opportunity is display interaction moiré where a rasterization or pixel pattern in the display interacts with a pattern in the image to create a moiré pattern. As mentioned, changing the relative size of the image can change or eliminate the moiré pattern on the display. Blurring the image can also eliminate the moiré at the cost of a less sharp image. I'd assume, a finer pitch display will be less likely to have noticeable moiré and any display moiré may be easier to correct by adjusting display resolution or image size because there are more pixels to play with.


Oct 16, 2017 at 03:31 PM
Bob Jarman
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p.1 #9 · p.1 #9 · Does anyone know how...


AuntiPode wrote:
Actually, there are two opportunities for moiré - the worst is sensor interaction moiré where the grid pattern of the sensor interacts with a pattern in the subject. It's worse because the image formed will contain the moiré pattern and any faithful print or display will show the moiré pattern, regardless of magnification. Many camera sensors are covered with a plate that slightly diffuses the light to reduce sensor pattern moiré. The other opportunity is display interaction moiré where a rasterization or pixel pattern in the display interacts with a pattern in the image to create a moiré pattern. As
...Show more

Karen,

Yes, my Oz buddy sent a set of actions that downsize across ranges of dimensions. Some work well, others very well depending.

Also TonyKuyper's sharpening action seems to help, although full sized remains best overall. So, not a camera or camera related matter but artifact of monitors and imagery....

Thanks for you explanation,

Bob




Oct 17, 2017 at 09:30 AM
RustyBug
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p.1 #10 · p.1 #10 · Does anyone know how...


Bob Jarman wrote:
So, not a camera or camera related matter


That's my take on it, too.



Oct 17, 2017 at 10:22 AM
sbeme
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p.1 #11 · p.1 #11 · Does anyone know how...


If I recall, the 5Ds is supposed to be more vulnerable to moire because of the absence of an anti-aliasing filter. Is that correct? and if so, Ben, have you run in to this. (I assume you eschew man-made objects in your nature shots and usually don't have to work around them).


Scott



Oct 17, 2017 at 10:34 AM
RustyBug
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p.1 #12 · p.1 #12 · Does anyone know how...


That would be the 5DsR (vs. 5Ds) with the "offset" AA filter.
It isn't actually a camera without an AA filter, it basically performs a shift the light path one direction, then, shift it back.

My Kodak SLR/C (14MP) was a true "no AA filter". As a primarily organic shooter, too ... I didn't experience much moire'. Mostly because I didn't shoot patterned items. But, when I did, then shooting softer glass, or softer lighting would typically keep the lowered contrast to retaining the frequency below that of outresolving the frequency of the sensor.

The only time I really experienced moire' was a pic of a tight knit polo golf shirt, with sharp telephoto (highly collimated) glass, stopped down, in high contrast light. Shooting organic subjects with wide angle lenses (WA lenses don't have the same level of collimation / resolving capability as tele's) ... never had an issue with moire'.

Given Ben's use of the 5DsR (with an AA filter, just offset), 50MP pixel frequency, organic subjects and UWA lenses ... I'd be surprised if Ben knows what the word means , let alone ever experienced it.



Oct 17, 2017 at 11:02 AM
sbeme
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p.1 #13 · p.1 #13 · Does anyone know how...


ah, yes sR (sir)


Oct 17, 2017 at 11:44 AM
dmacmillan
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p.1 #14 · p.1 #14 · Does anyone know how...


AuntiPode wrote:
When the grid of a fence makes your eyes take offense, that's a moiré.

<ducking>

50 lashes with a wet noodle for your bad pun on a song made famous by Dean Martin!



Oct 17, 2017 at 02:38 PM
AuntiPode
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p.1 #15 · p.1 #15 · Does anyone know how...


As my spouse who scuba dives like to sing:

"When an eel bites your leg and the pain makes you beg, that's a moray."



Oct 17, 2017 at 05:38 PM





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