Moiré disaster on the E-5

Started Jul 10, 2013 | Discussions
Barry Stewart
Veteran MemberPosts: 8,049Gear list
Like?
John
In reply to John Sheehy, Jul 12, 2013

John Sheehy wrote:

Your resizing software sucks or has the wrong settings. It is point-sampling, a good tool for a few select applications, but not for general image resizing.

I agree, iPhoto is good for a few select applications. I see no user-settings that would help it. I was also seeing this wood grain in PS Elements.

What is an alternative to "point-sampling?"

Your original is slightly aliased. Bad software/settings exaggerate that exponentially. You would have had no problem, for instance, had the original been shot at an f-stop with significant pixel-level blur due to diffraction, or a soft, wide-open lens.

It was the ZD-50, at F/3.5, which is about as loose as I'd want to shoot portraits, as the depth of field is very unforgiving if I shoot any more open (nose in focus, eyes not, for example.)

-- hide signature --

--

Barry

 Barry Stewart's gear list:Barry Stewart's gear list
Olympus C-5060 Wide Zoom Olympus Tough TG-3 Olympus E-1 Olympus PEN E-PL5 Olympus E-M1 +10 more
Reply   Reply with quote   Complain
Barry Stewart
Veteran MemberPosts: 8,049Gear list
Like?
Olyflyer
In reply to olyflyer, Jul 12, 2013

Thanks  for the in-depth response. I hope others can benefit from it as well.

-- hide signature --

Barry

 Barry Stewart's gear list:Barry Stewart's gear list
Olympus C-5060 Wide Zoom Olympus Tough TG-3 Olympus E-1 Olympus PEN E-PL5 Olympus E-M1 +10 more
Reply   Reply with quote   Complain
olyflyer
Forum ProPosts: 22,740
Like?
Re: MP race
In reply to Stacey_K, Jul 12, 2013

Stacey_K wrote:

olyflyer wrote:

But... there is no contradiction between color accuracy and high resolution. I have no problems with the color out of my D800 and never heard anyone complaining about them, quite the opposite, so I don't understand the discussion.

The colors/OOC jepgs from my E1 are much better than anything I have gotten from my D7000, so much so I now am using a D200 for much of my work.

That's OK, taste is different, there is no right or wrong in my opinion. I preferred the E3 before the E1 and the E500 and still do. When I look at my old E500 images I really don't like the colors compared to the other cameras I had or still have. The D200 is also a CCD camera, so perhaps that's the reason why you like it more than the D7000, though I never had the D7000, so I have no idea about that one.

Reply   Reply with quote   Complain
John Sheehy
Forum ProPosts: 15,982
Like?
Re: John
In reply to Barry Stewart, Jul 12, 2013

Barry Stewart wrote:

John Sheehy wrote:

Your resizing software sucks or has the wrong settings. It is point-sampling, a good tool for a few select applications, but not for general image resizing.

I agree, iPhoto is good for a few select applications.

I meant its resizing method sucks as you used it; I don't know if it has other options, or what else it does.  I would look for resampling options for both on-screen and for explicit resizing in the menus.

I see no user-settings that would help it. I was also seeing this wood grain in PS Elements.

What is an alternative to "point-sampling?"

Lanczos, Bicubic and Bilinear are the more common ones.

Your original is slightly aliased. Bad software/settings exaggerate that exponentially. You would have had no problem, for instance, had the original been shot at an f-stop with significant pixel-level blur due to diffraction, or a soft, wide-open lens.

It was the ZD-50, at F/3.5, which is about as loose as I'd want to shoot portraits, as the depth of field is very unforgiving if I shoot any more open (nose in focus, eyes not, for example.)

I wasn't trying to suggest that you have used a softer lens, per se; the aliasing in the full res image was marginal.  I was just saying that if the original image were soft enough, the aliasing would be less, even with the poor downsizing method.

Reply   Reply with quote   Complain
John Sheehy
Forum ProPosts: 15,982
Like?
Re: What disaster? Stacey
In reply to Barry Stewart, Jul 12, 2013

Barry Stewart wrote:

Stacey_K wrote:

If it doesn't show at 100%, it's -not- the camera. Software editing programs can do this at various "magnifications" soft proofing.

That's what I'm hearing from various people here. I guess I don't shoot a lot of suits like this one, because this is the first I've seen of this problem.

That doesn't mean that you haven't been seeing every image distorted; this was just the most obvious.  I can guarantee you that you've been seeing a lot more noise than the camera really has.

Are you saying that other cameras would be equally as likely to have this problem?

The camera is the smallest factor, when you downsize with a poor method.

Reply   Reply with quote   Complain
seilerbird666
Senior MemberPosts: 1,101
Like?
Barry - Everyone is wrong
In reply to Barry Stewart, Jul 12, 2013

One of the first basic programs I wrote back in the early 80s created moire patterns.

The problem is not with the camera.

The problem is not with the software.

The moire pattern is caused by interference between the lines on the suit and the lines of pixels on your monitor. Look at the image on a different monitor and it will act differently. That is why most of us here cannot see the problem, we are viewing it on different monitors.

-- hide signature --

My photos:
picasaweb.google.com/seilerbird

Reply   Reply with quote   Complain
Stacey_K
Veteran MemberPosts: 4,990Gear list
Like?
Re: MP race
In reply to olyflyer, Jul 12, 2013

olyflyer wrote:

Stacey_K wrote:

olyflyer wrote:

But... there is no contradiction between color accuracy and high resolution. I have no problems with the color out of my D800 and never heard anyone complaining about them, quite the opposite, so I don't understand the discussion.

The colors/OOC jepgs from my E1 are much better than anything I have gotten from my D7000, so much so I now am using a D200 for much of my work.

That's OK, taste is different, there is no right or wrong in my opinion.

I see a digital camera body more like "film", they each have their own unique characteristics. I never cared for velvia nor did I like kodachrome. One of my fav films was that kodak PJM multispeed pro color print film, loved the colors and it had insane exposure latitude. You could over expose and the grain all but disappeared but was still very usable at iso640-800. The E1 files remind me a lot of that film and so does the D200. The speed limitations are similar as well. I still wish Olympus had stuck with the kodak sensors and kept the same look to the files the E1 has rather than trying to "be more like a canikon"..

-- hide signature --

Stacey

 Stacey_K's gear list:Stacey_K's gear list
Nikon D200 Nikon D700 Nikon D7000 Nikon D800 Nikon AF Nikkor 105mm f/2D DC +14 more
Reply   Reply with quote   Complain
Stacey_K
Veteran MemberPosts: 4,990Gear list
Like?
Nope, you're wrong :)
In reply to seilerbird666, Jul 12, 2013

seilerbird666 wrote:

One of the first basic programs I wrote back in the early 80s created moire patterns.

The problem is not with the camera.

The problem is not with the software.

The moire pattern is caused by interference between the lines on the suit and the lines of pixels on your monitor. Look at the image on a different monitor and it will act differently. That is why most of us here cannot see the problem, we are viewing it on different monitors.

I don't agree. I opened the original file in CS2 and no moire at 100% or 50%. At 33% it was pretty ugly. I then down sampled the file to the same 33% size using bicubic and no moire viewed at 100% after being made 33% of the original size. If what you say is true, the moire would still be there after down sampling to the same size I saw the moire patterns previewing it in PS. These "preview down samplers" are written for speed of rendering, not for quality. It's why they can create ugly artifacts. You can never go by what you see in them, especially in sizes other then divisible by 2 ones. If I need to get a decent preview at less than 100% I always use 50%, 25%, 12.5% etc.

-- hide signature --

Stacey

 Stacey_K's gear list:Stacey_K's gear list
Nikon D200 Nikon D700 Nikon D7000 Nikon D800 Nikon AF Nikkor 105mm f/2D DC +14 more
Reply   Reply with quote   Complain
Airmel
Regular MemberPosts: 275Gear list
Like?
Re: Not nearly the same ...
In reply to John Sheehy, Jul 13, 2013

John Sheehy wrote:

Airmel wrote:

Great Bustard wrote:

...the simple fix is more pixels. which so many fight against. The more pixels the sensor has, the weaker the AA filter needs to be to avoid aliasing.

All other things being the same, the use of a higher resolution sensor ("more pixels") requires Anti Aliasing with a correspondingly higher cutoff frequency.

It's hard to tell why you're saying this. You said the same thing as the Great Bustard, but in different words. An infinite cutoff frequency would be no filter at all.

The issues are so simple when you put your DSLR or 4/3 lens on a camera like the Pentax Q with an adapter; you can simulate what you system would be like (at least in the center of the frame) with hundreds of MPs; no significant spatial artifacts, and a virtually analog capture of the lens projection with only lens issues remaining. The images look much, much more natural and artifact-free, than cropping from the same lens with the camera made to work with the lens (large sensor with coarse pixels).

The fact is, in their sweet spots with good technique, DSLR and 4/3 lenses can have far too much resolution for their sensors. Those who claim otherwise are generally people who ENJOY aliasing artifacts, and can't tell them from accurate, natural imaging due to a weak right hemisphere.

Well as a matter of fact, what I said is quite different that what GB said. An anti-alias filter with a higher cutoff frequency is not "weaker", it simply utilizes a higher cutoff frequency.

The required cutoff frequency is well defined by the sampling theorem. It is directly related to the sampling frequency and is nowhere near infinite. The more pixels per unit distance, the higher the cutoff frequency of the anti-alias filter will need to be. Very simple really.

Now as a practical matter, it turns out that virtually all optical anti-alias filters are very poor performers. The technology simply doesn't exist to build a cheap optical low pass filter which has anywhere near the performance of its electronic signal processing counterpart. For this reason you might rightly refer to all optical anti-alias filters as "weak".

However so, there is no validity to the notion that an anti-alias filter with a higher cutoff frequency is "weaker" in some way. If you adjusted your sports car's speed limiter from 125 MPH to 155 MPH, you wouldn't say the speed limiter is now "weaker". It would simply be tuned to a different speed limit. The speed limiter's performance above and below the new limit would be the same as that seen above and below the previous limit.

-- hide signature --

AirMel

 Airmel's gear list:Airmel's gear list
Olympus Stylus 1 Olympus E-M1 Olympus OM-D E-M10 Olympus Zuiko Digital ED 12-60mm 1:2.8-4.0 SWD Olympus Zuiko Digital ED 50-200mm 1:2.8-3.5 SWD +9 more
Reply   Reply with quote   Complain
seilerbird666
Senior MemberPosts: 1,101
Like?
Re: Nope, you're wrong :)
In reply to Stacey_K, Jul 13, 2013

Stacey_K wrote:

seilerbird666 wrote:

One of the first basic programs I wrote back in the early 80s created moire patterns.

The problem is not with the camera.

The problem is not with the software.

The moire pattern is caused by interference between the lines on the suit and the lines of pixels on your monitor. Look at the image on a different monitor and it will act differently. That is why most of us here cannot see the problem, we are viewing it on different monitors.

I don't agree. I opened the original file in CS2 and no moire at 100% or 50%. At 33% it was pretty ugly. I then down sampled the file to the same 33% size using bicubic and no moire viewed at 100% after being made 33% of the original size. If what you say is true, the moire would still be there after down sampling to the same size I saw the moire patterns previewing it in PS. These "preview down samplers" are written for speed of rendering, not for quality. It's why they can create ugly artifacts. You can never go by what you see in them, especially in sizes other then divisible by 2 ones. If I need to get a decent preview at less than 100% I always use 50%, 25%, 12.5% etc.

-- hide signature --

Stacey

Stacy you do not understand what moire is. It is a distortion between two different sets of lines.

Those two sets of lines are on the suit and the lines on the monitor. There is simply no other way moire can happen. You want proof? Conduct those same tests on a totally different monitor and you will get totally different results.

-- hide signature --

My photos:
picasaweb.google.com/seilerbird

Reply   Reply with quote   Complain
John Sheehy
Forum ProPosts: 15,982
Like?
Re: Nope, you're wrong :)
In reply to seilerbird666, Jul 13, 2013

seilerbird666 wrote:

Stacy you do not understand what moire is. It is a distortion between two different sets of lines.

It's a pattern created by the juxtaposition of other patterns.  In the OP's case, it is a matter of the white spots going in and out of phase with the resultant pixels; white rings where the resultant pixels came from white spots, and black rings when they came from black background.  It has nothing to do with the monitor directly; the only affect the monitor has is that the OS knows what the monitor resolution is, and the app uses this information to know what the pixel dimensions of its display area are.  Two completely different monitors, with the same pixel count, will give the same moire.  Two windows of the same size on monitors with different resolutions will also give different results.  The only way that a monitor can directly cause moire is if the monitor is getting a resolution from the graphics chip that is not its native resolution, and the monitor scales it, but this generally only happens with TV monitors, and they usually have built-in scaling that doesn't create moire.

Reply   Reply with quote   Complain
Great Bustard
Forum ProPosts: 22,413
Like?
By "weak AA filter"...
In reply to Airmel, Jul 13, 2013

Airmel wrote:

John Sheehy wrote:

Airmel wrote:

Great Bustard wrote:

...the simple fix is more pixels. which so many fight against. The more pixels the sensor has, the weaker the AA filter needs to be to avoid aliasing.

All other things being the same, the use of a higher resolution sensor ("more pixels") requires Anti Aliasing with a correspondingly higher cutoff frequency.

It's hard to tell why you're saying this. You said the same thing as the Great Bustard, but in different words. An infinite cutoff frequency would be no filter at all.

The issues are so simple when you put your DSLR or 4/3 lens on a camera like the Pentax Q with an adapter; you can simulate what you system would be like (at least in the center of the frame) with hundreds of MPs; no significant spatial artifacts, and a virtually analog capture of the lens projection with only lens issues remaining. The images look much, much more natural and artifact-free, than cropping from the same lens with the camera made to work with the lens (large sensor with coarse pixels).

The fact is, in their sweet spots with good technique, DSLR and 4/3 lenses can have far too much resolution for their sensors. Those who claim otherwise are generally people who ENJOY aliasing artifacts, and can't tell them from accurate, natural imaging due to a weak right hemisphere.

Well as a matter of fact, what I said is quite different that what GB said. An anti-alias filter with a higher cutoff frequency is not "weaker", it simply utilizes a higher cutoff frequency.

The required cutoff frequency is well defined by the sampling theorem. It is directly related to the sampling frequency and is nowhere near infinite. The more pixels per unit distance, the higher the cutoff frequency of the anti-alias filter will need to be. Very simple really.

Now as a practical matter, it turns out that virtually all optical anti-alias filters are very poor performers. The technology simply doesn't exist to build a cheap optical low pass filter which has anywhere near the performance of its electronic signal processing counterpart. For this reason you might rightly refer to all optical anti-alias filters as "weak".

However so, there is no validity to the notion that an anti-alias filter with a higher cutoff frequency is "weaker" in some way. If you adjusted your sports car's speed limiter from 125 MPH to 155 MPH, you wouldn't say the speed limiter is now "weaker". It would simply be tuned to a different speed limit. The speed limiter's performance above and below the new limit would be the same as that seen above and below the previous limit.

...I mean that the size of the blur is less as a proportion of the image.  For example, if an AA filter had a blur radius of 1.5 pixels, then a 24 MP sensor would have half the blur (twice as weak) as a 6 MP sensor.

Reply   Reply with quote   Complain
rovingtim
Veteran MemberPosts: 7,982
Like?
Re: Not nearly the same ...
In reply to Airmel, Jul 13, 2013

Airmel wrote:

The technology simply doesn't exist to build a cheap optical low pass filter which has anywhere near the performance of its electronic signal processing counterpart. For this reason you might rightly refer to all optical anti-alias filters as "weak".

Perhaps optical AA's aren't as efficient as their electronic counterpart, but I think the key is more likely to be "The technology simply doesn't exist to build a cheap optical low pass filter ..."

I suspect this has more to do with why the industry has campaigned to wean photographers off AA's. Additionally, I think it could be argued that the 'carrot' they used is the appearance of higher resolution that results from the artifacts.

And here we are.

Reply   Reply with quote   Complain
rovingtim
Veteran MemberPosts: 7,982
Like?
Re: By "weak AA filter"...
In reply to Great Bustard, Jul 13, 2013

I agree that at higher resolutions there are other things in the optical chain that can act as a very poor AA to remove aliasing. However, if the image is in focus and sharp, you get exactly the same aliasing problems at 100% on high resolution cameras as you do at low resolution cameras.

Reply   Reply with quote   Complain
Great Bustard
Forum ProPosts: 22,413
Like?
Re: By "weak AA filter"...
In reply to rovingtim, Jul 13, 2013

rovingtim wrote:

I agree that at higher resolutions there are other things in the optical chain that can act as a very poor AA to remove aliasing. However, if the image is in focus and sharp, you get exactly the same aliasing problems at 100% on high resolution cameras as you do at low resolution cameras.

Well, no, you don't.  The reason is that diffraction, at the pixel level, also begins to act as a type of AA filter.  Indeed, the ideal pixel count for a sensor, in terms of IQ, is a pixel count so high that there is no need for an AA filter at all, as diffraction, even wide open, will do the job.

However, let's assume an aperture wide enough that diffraction is a non-issue on the pixel level.  Then yes, you are correct, for 100% viewing of the photo.  However, when viewing the photos at the same size, the photo made from more pixels will render the scene considerably more accurately than the photo made from fewer pixels.  The question, of course, is if the display size, viewing distance, and visual acuity such that the difference can be seen.

Reply   Reply with quote   Complain
Great Bustard
Forum ProPosts: 22,413
Like?
Ironically...
In reply to rovingtim, Jul 13, 2013

rovingtim wrote:

Airmel wrote:

The technology simply doesn't exist to build a cheap optical low pass filter which has anywhere near the performance of its electronic signal processing counterpart. For this reason you might rightly refer to all optical anti-alias filters as "weak".

Perhaps optical AA's aren't as efficient as their electronic counterpart, but I think the key is more likely to be "The technology simply doesn't exist to build a cheap optical low pass filter ..."

I suspect this has more to do with why the industry has campaigned to wean photographers off AA's. Additionally, I think it could be argued that the 'carrot' they used is the appearance of higher resolution that results from the artifacts.

And here we are.

...as pixel count increases, the quality of the AA filter can afford to decrease, so it makes it cheaper and easier to manufacture the AA filter.

Reply   Reply with quote   Complain
rovingtim
Veteran MemberPosts: 7,982
Like?
Re: By "weak AA filter"...
In reply to Great Bustard, Jul 13, 2013

Great Bustard wrote:

Well, no, you don't. The reason is that diffraction, at the pixel level, also begins to act as a type of AA filter.

Assuming lenses of equal aperture/sharpness ... right?

Reply   Reply with quote   Complain
rovingtim
Veteran MemberPosts: 7,982
Like?
Re: Ironically...
In reply to Great Bustard, Jul 13, 2013

Great Bustard wrote:

rovingtim wrote:

Airmel wrote:

The technology simply doesn't exist to build a cheap optical low pass filter which has anywhere near the performance of its electronic signal processing counterpart. For this reason you might rightly refer to all optical anti-alias filters as "weak".

Perhaps optical AA's aren't as efficient as their electronic counterpart, but I think the key is more likely to be "The technology simply doesn't exist to build a cheap optical low pass filter ..."

I suspect this has more to do with why the industry has campaigned to wean photographers off AA's. Additionally, I think it could be argued that the 'carrot' they used is the appearance of higher resolution that results from the artifacts.

And here we are.

...as pixel count increases, the quality of the AA filter can afford to decrease, so it makes it cheaper and easier to manufacture the AA filter.

Can you explain this further, please?

Reply   Reply with quote   Complain
Raist3d
Forum ProPosts: 32,723Gear list
Like?
That's just the downsampling algorithm of the program you are using...
In reply to Barry Stewart, Jul 13, 2013

Resize in a high quality program and hopefully this shouldn't happen that bad.

-- hide signature --

Raist3d/Ricardo (Photographer, software dev.)- I photograph black cats in coal mines at night...
“The further a society drifts from truth the more it will hate those who speak it.” - George Orwell

Reply   Reply with quote   Complain
John Sheehy
Forum ProPosts: 15,982
Like?
Re: Not nearly the same ...
In reply to Airmel, Jul 13, 2013

Airmel wrote:

Well as a matter of fact, what I said is quite different that what GB said. An anti-alias filter with a higher cutoff frequency is not "weaker", it simply utilizes a higher cutoff frequency.

An AA filter is usually two sheets of birefringent material, each of which takes a point of light, and turns it into two points of light.  They are layered at 90 degree angles from each other, to result in 4 points of light.  This is a dirty way to do it, but this is how it is done.The larger the spacing between the points, the stronger the AA filter is said to be.  Even if we are talking about the spacing of the four points relative to pixel spacing, it is still true that a weaker AA filter (as measured in pixels) is needed for higher pixel densities, because diffraction and other optical issues are going to attenuate higher frequencies, anyway.  A sensor with large pixels has to deal with the possibility of a very sharp lens with very little diffraction (say, a Sigma 35mm f/1.4 art lens at f/2, or wherever its sweet spot is).

The required cutoff frequency is well defined by the sampling theorem. It is directly related to the sampling frequency and is nowhere near infinite.

I didn't say that it was infinite in any actual AA filter.  I said that one that was designed to be infinite would simply not exist at all.  I said that because your language seemed to suggest to someone less in tune with things that there was some special achievement in designing an AA filter with a "high cut-off frequency", when the reality is that a high-cutoff is, in actuality, almost no filtration at all.

The more pixels per unit distance, the higher the cutoff frequency of the anti-alias filter will need to be. Very simple really.

Now as a practical matter, it turns out that virtually all optical anti-alias filters are very poor performers. The technology simply doesn't exist to build a cheap optical low pass filter which has anywhere near the performance of its electronic signal processing counterpart. For this reason you might rightly refer to all optical anti-alias filters as "weak".

AFAIK, they all turn one point into 4, so strength/weakness can on refer, in practical concerns, to the spacing of the 4 points, either absolutely or relatively.

However so, there is no validity to the notion that an anti-alias filter with a higher cutoff frequency is "weaker" in some way. If you adjusted your sports car's speed limiter from 125 MPH to 155 MPH, you wouldn't say the speed limiter is now "weaker". It would simply be tuned to a different speed limit. The speed limiter's performance above and below the new limit would be the same as that seen above and below the previous limit.

Active analogies for passive phenomena?

Reply   Reply with quote   Complain
Keyboard shortcuts:
FForum MMy threads