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Author Topic: 1Ds MKIII and Optical Low Pass filtering  (Read 149451 times)

Lin Evans

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1Ds MKIII and Optical Low Pass filtering
« Reply #60 on: October 24, 2007, 01:10:57 pm »

Minor correction Ray:

The Sigma SD14 produces a 4.67 megapixel output file from 14 million sampling sites. The optical resolution for "all" colors and B&W is very close to 1800 lines per image height horizontally and vertically which puts it around the 9-10 megapixel equivalence in b&w and better than 12 megapixel CFA equivalency for reds.


Best regards,

Lin


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Well, the article certainly provides an insight into why it is thought AA filters are needed, but doesn't really explain why Bayer type cameras without either AA filters or microlenses, those ridiculously expensive MFDBs that knock your socks off, get by without them. (I think I'm right in saying that MFDBs do not have microlenses, but if I'm wrong I'm sure you'll correct me   ).

It's interesting to note also that Sigma's Foveon cameras are typically low resolution (the SD14 just 4.3mp) yet the clarity and 3-dimensionality is much admired by some. The cameras are also criticised for producing lots of aliasing and artificial detail, due to lack of an AA filter, which cause the images to appear sharper than they actually are, and no doubt some of that extra clarity is due to the fact that all the pixels are real, ie. non-interpolated.

Nevertheless, if aliasing is not such a big disadvantage with such a low-pixel-density sensor as the SD14, one wonders if it is really necessary with higher pixel density cameras such as the 1Ds3 and particularly the 400D and 40D.
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Ray

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« Reply #61 on: October 24, 2007, 01:51:21 pm »

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Minor correction Ray:

The Sigma SD14 produces a 4.67 megapixel output file from 14 million sampling sites. The optical resolution for "all" colors and B&W is very close to 1800 lines per image height horizontally and vertically which puts it around the 9-10 megapixel equivalence in b&w and better than 12 megapixel CFA equivalency for reds.
Best regards,

Lin
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Okay! 4.3 or 4.7, lets not nit pick. We're all waiting for 10mp.
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Lin Evans

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« Reply #62 on: October 24, 2007, 02:23:02 pm »

LOL - what would you use for a lens? The 3.4 produces over 1500 lines, the 4.67 about 1760 so the 10 in that progression would produce around 3700 lines horiz and vertical - probably out resolve any current 35mm lenses??

Best regards,

Lin

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Okay! 4.3 or 4.7, lets not nit pick. We're all waiting for 10mp.
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sojournerphoto

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« Reply #63 on: October 24, 2007, 04:31:34 pm »

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LOL - what would you use for a lens? The 3.4 produces over 1500 lines, the 4.67 about 1760 so the 10 in that progression would produce around 3700 lines horiz and vertical - probably out resolve any current 35mm lenses??

Best regards,

Lin
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I don't know if it would outresolve all curent 35mm lenses, but I think that the ability to outresolve all current lenses would be a good thing. Basically that would lead to oversampling, which whilst not efficient, may give the best results. I think the sigma sensor has a crop factor of 1.5 so 4.7 Mp* 1.5^2 is around 10.6Mp. If the noise is under control I would be very happy with that I suspect (though perhaps I'd really want 25MP foveon...)

Mike
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John Sheehy

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« Reply #64 on: October 24, 2007, 04:51:51 pm »

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Minor correction Ray:

The Sigma SD14 produces a 4.67 megapixel output file from 14 million sampling sites. The optical resolution for "all" colors and B&W is very close to 1800 lines per image height horizontally and vertically which puts it around the 9-10 megapixel equivalence in b&w and better than 12 megapixel CFA equivalency for reds.[a href=\"index.php?act=findpost&pid=148420\"][{POST_SNAPBACK}][/a]

No, the Sigma doesn't do that many lines.  It can do that many "lucky lines" with luck of alignment.  The same lines can go totally unseen, with no contrast whatsoever, just by shifting 1/2 pixel relative to the sensor.  That is not "resolution".  A slight mismatch in frequency results in a low-frequency modulation between no lines and high-contrast lines.
« Last Edit: October 25, 2007, 01:18:17 pm by John Sheehy »
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Lin Evans

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« Reply #65 on: October 24, 2007, 05:30:02 pm »

Hey John,

We've been down this road before. Indeed it does do 1760 lines vertical and horizontally measured as all others have been on b&w standardized optical resolution charts. "Luck" has nothing to do with it.

I have no idea where you come up with these silly arguments about Sigma resolution. I've been measuring it and using the SD9, SD10 and SD14 since they were in beta and the optical resolution is precisely as measured for all colors. Really you need to stick to dealing with things you actually have experience with rather than introducing FUD about a camera you have no hands-on experience with.

Best regards,

Lin

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No, the Sigma doesn't do that many lines.  It can do that many "lucky lines" with luck of alignment.  The same lines can go totally unseen, with no contrast whatsoever, just by shifting 1/2 pixel relative to the sensor.  That is not "resolution".  A slight mismatch in frequency result in a low-frequency modulation between no lines and high-contrast lines.
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Lin Evans

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« Reply #66 on: October 24, 2007, 05:31:40 pm »

Hi Mike,

Actually the Sigma's all have a crop factor of 1.7x.

Best regards,

Lin

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I don't know if it would outresolve all curent 35mm lenses, but I think that the ability to outresolve all current lenses would be a good thing. Basically that would lead to oversampling, which whilst not efficient, may give the best results. I think the sigma sensor has a crop factor of 1.5 so 4.7 Mp* 1.5^2 is around 10.6Mp. If the noise is under control I would be very happy with that I suspect (though perhaps I'd really want 25MP foveon...)

Mike
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Graeme Nattress

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« Reply #67 on: October 24, 2007, 06:41:57 pm »

Lin, they're not silly arguments, they're based upon sampling theory and the lack of optical low pass filtering on the Sigma cameras. So if you've got 2640 x 1760, you should be able to measure that, however, you'll also get nasty aliasing. You don't get one without the other. Some people like aliasing, others don't. I personally like to keep it at a minimum. That's why I use high resolution zone plates for testing resolution and aliasing so that I can easily see what's going on. However, I do note from the Foveon pdfs that they do say that the requirement for optical low pass filtering is not removed by their chip design.

Graeme

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Hey John,

We've been down this road before. Indeed it does do 1760 lines vertical and horizontally measured as all others have been on b&w standardized optical resolution charts. "Luck" has nothing to do with it.

I have no idea where you come up with these silly arguments about Sigma resolution. I've been measuring it and using the SD9, SD10 and SD14 since they were in beta and the optical resolution is precisely as measured for all colors. Really you need to stick to dealing with things you actually have experience with rather than introducing FUD about a camera you have no hands-on experience with.

Best regards,

Lin
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John Sheehy

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« Reply #68 on: October 24, 2007, 06:55:40 pm »

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Hey John,

We've been down this road before. Indeed it does do 1760 lines vertical and horizontally measured as all others have been on b&w standardized optical resolution charts. "Luck" has nothing to do with it.

Luck has everything to do with it.  Lines that are converging will naturally have zones of high contrast, but also zones that are almost completely grey.  The grey "crossover" zones in the converging lines are just as significant as the areas with contrast; you just want to see the good parts and ignore the trash, and count only the good parts as a quality of the imaging.  The people who decided how a resolution test should be interpreted did not bother to stop to think about aliasing, so you relish this loophole to pretend that artifical resolution is something good.

Quote
I have no idea where you come up with these silly arguments about Sigma resolution. I've been measuring it and using the SD9, SD10 and SD14 since they were in beta and the optical resolution is precisely as measured for all colors. Really you need to stick to dealing with things you actually have experience with rather than introducing FUD about a camera you have no hands-on experience with.
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I don't need my own Sigma and test chart to see that it violates the basic rules of consistent imaging.  Chance of pixel/subject alignment is crucial for an appearance of high resolution.

You should know very well that the camera can't resolve *ANY* lines at all at the nyquist if you just move the sensor just 1/2 pixel.  You don't see this with the converging lines, because some part of them is always guaranteed to have some contrast.  In the experiments that other people did with printed sheets of checkerboard patterns at the nyqist, the checkerboard only appeared in a fraction of the checkerboard areas.  Large areas of grey appeared as well.  This is not what was envisioned in the original concept of "resolution", I would think.  Play with your "resolution" loophole all you want, but aliased imaging falls flat on its face when you qualify with "consistent resolution with accurately placed points and edges", which is what matters most.

More pixels is what cameras need; not aliasing, not anti-aliasing.  In the interim, anti-aliasing is the reasonable solution.
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Lin Evans

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« Reply #69 on: October 24, 2007, 07:16:10 pm »

Hi Graeme,

It's a silly argument to tell me that the resolution of my camera is not what I measure it to be. I'm not a beginner either with sampling theory or Physics (Masters Degree) or with digital cameras.

Whether one believes that a low pass filter is necessary is a subjective issue and real-world results tell me that I prefer the IQ from my SD14 to any of my other (many) CFA dSLR's and fixed lens digital cameras. I'm comparing it with my Canon D30, 10D, 1D, 1DS, 1D Mark II and 40D. I'm comparing it with my Nikon D2Xs and with my Kodak 16 back and my Kodak DCS-760 which I "prefer" with the AA filter removed.

The term "nasty aliasing" is another "subjective issue". Is there some stairstep aliasing especially on some man made objects? Yes. Can I deal with it in post, very easily on a selective basis? Yes. Is it an issue for "most" of my photography? Absolutely not. In wildlife and nature photos I get amazing enlargements from my SD14 and even from my SD10. I have images posted at PMA at A0 size and larger which have no visible aliasing and have received rave reviews. So the bottom line is it's very easy for me to compare the output with that of my numerous CFA counterparts and I like what I get. The optical resolution is what it measures. There are "fewer" artifacts in the capture than from the CFA counterparts.

Sampling theory is fine to debate, but real world results are what work for the photographer.

Best regards,

Lin

Quote
Lin, they're not silly arguments, they're based upon sampling theory and the lack of optical low pass filtering on the Sigma cameras. So if you've got 2640 x 1760, you should be able to measure that, however, you'll also get nasty aliasing. You don't get one without the other. Some people like aliasing, others don't. I personally like to keep it at a minimum. That's why I use high resolution zone plates for testing resolution and aliasing so that I can easily see what's going on. However, I do note from the Foveon pdfs that they do say that the requirement for optical low pass filtering is not removed by their chip design.

Graeme
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« Last Edit: October 24, 2007, 07:31:57 pm by Lin Evans »
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Lin Evans

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« Reply #70 on: October 24, 2007, 07:30:00 pm »

John,

The "bottom line" is "results". I know what results I get from my Sigma and from my CFA cameras and which I and my customer's prefer.  You can argue sampling "theory" till the cows come home and that doesn't change real world "results."

Mike Chaney (author of Qimage) has about put his Canon 5D to rest since he began using the SD14 - he has good reasons and is as good at "pixel peeping" as anyone around. The real world performance in produced IQ of the SD14 is outstanding and that's an incontrovertible fact. The detail and sharpness in enlargements are superior to what I get from my CFA counterparts. After 40+ years of making a pretty good living doing this I really do know what makes a good image!

As I said, we've been down this road before. You see aliasing everywhere you look - I'm amazed that you ever really "enjoy" an image, LOL.  Thousands of professionals in the photography business passing by the Sigma booth at Photokina and PMA concur that the images produced by the SD14 are outstanding. That's what's important to me. I know what works and what sells and what people like. I'm not selling images to sampling theory pixel peepers, I'm selling to patrons of fine art and their opinions are what count.

So keep your head in those figures and sampling theory and keep wishing for something better - maybe it will happen for you. For me, I'll do just fine with my "nasty aliasing" and SD14 thank you...

Lin


Quote
Luck has everything to do with it.  Lines that are converging will naturally have zones of high contrast, but also zones that are almost completely grey.  The grey "crossover" zones in the converging lines are just as significant as the areas with contrast; you just want to see the good parts and ignore the trash, and count only the good parts as a quality of the imaging.  The people who decided how a resolution test should be interpreted did not bother to stop to think about aliasing, so you relish this loophole to pretend that artifical resolution is something good.
I don't need my own Sigma and test chart to see that it violates the basic rules of consistent imaging.  Chance of pixel/subject alignment is crucial for an appearance of high resolution.

You should know very well that the camera can't resolve *ANY* lines at all at the nyquist if you just move the sensor just 1/2 pixel.  You don't see this with the converging lines, because some part of them is always guaranteed to have some contrast.  In the experiments that other people did with printed sheets of checkerboard patterns at the nyqist, the checkerboard only appeared in a fraction of the checkerboard areas.  Large areas of grey appeared as well.  This is not what was envisioned in the original concept of "resolution", I would think.  Play with your "resolution" loophole all you want, but aliased imaging falls flat on its face when you qualify with "consistent resolution with accurately placed points and edges", which is what matters most.

More pixels is what cameras need; not aliasing, not anti-aliasing.  In the interim, anti-aliasing is the reasonable solution.
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Graeme Nattress

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« Reply #71 on: October 24, 2007, 08:11:27 pm »

If you like the look of aliasing artifacts or not, that's subjective. That they exist, and can be measured is not subjective but objective. Quite frankly, if you had a detailed enough resolution chart, you'd still be measuring resolution way beyond the pixels on your sensor if you don't stop when aliasing starts to occur. It's a joke to suggest that heavily aliased data is real resolution when it's an undesirable artifact. If you could keep your resolution as-is, but not have any aliasing, would that not be beneficial to your images?

Graeme
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JeffKohn

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« Reply #72 on: October 24, 2007, 11:36:02 pm »

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If you could keep your resolution as-is, but not have any aliasing, would that not be beneficial to your images?
Graeme
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But that's the problem, you cannot keep resolution as-is without any aliasing. For some types of images, a bit of aliasing is preferable to the detail loss from an AA filter.

Maybe I don't want it completely gone, but defintitely very weak. For instance the D70 was known for having a fairly weak AA filter, and I never had any problems with moire or obvious aliasing. What's disappointing to some is that on the newer DSLR's there seems to be a trend towards stronger filters, not weaker.
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Lin Evans

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« Reply #73 on: October 24, 2007, 11:49:17 pm »

Hi Graeme,

This is where sampling theory and photographic reality collide. When I look at a b&w resolution chart at Nyquist a CFA sensor produces mush. When I shoot a landscape with grass, pine needles, leaves, etc., and enlarge a CFA print I get to a point where "mush" is very apparent. When nine converging lines on a resolution chart can no longer be resolved the AA filter produces a blob of indistinguishable grey plus color moire. In real-world photography this point is evident throughout when I reach the visible limits of resolution. These artifacts are far more objectionable to me than what you describe.

When my SD10 or SD14 stop resolving nine converging lines, I see five lines. Is this "real"? No - it's false detail but I still see "lines" not mush. Whether I see five blades of grass in my enlargement where there should be nine, or five pine needles where there should be nine on distant trees is largely unimportant as long as I still see something which resembles grass or pine needles or fur on wildlife (whose counting?). In my enlargements this false detail looks much more realistic than having an indistinguishable blob at the point of resolution exhaustion.

Would I like more "resolution?" Sure. But no matter how much "resolution" I have, an antialiasing filter simply at some point in the equation produces moire and blur which I don't want in my enlargements.

In the real world this lets me make larger prints and tighter crops  from my Foveon based Sigma than with even my 12 megapixel CFA sensor and "still" hold the interest of my audience. The reality is that with AA filtering not having visible stairstep aliasing eventually causes color moire and resolution extinction blur and having more resolution only pushes the point at which it appears further along the enlargement scale, it doesn't prevent it. All that it does is soften the edges and smooth out stairsteps. For some that may be a wonderful thing, but my walls are full of huge prints which show no visible aliasing and that's what I want an what my customers want.

Why do you think AA filters are rarely used on MF backs??? Why did Kodak not use one on their 14 series and why did they have a removable AA filter on earlier DCS pro-line cameras??  It's because for many jobs it produces a superior product - not "nasty aliasing". Yes indeed whether or not one "likes" the look of the image (not likes or dislikes aliasing) is the true issue. One doesn't look at the printed image from an inch away and never see a single pixel - that's what interpolation is all about. The issue of "aliasing" with the Sigma/Foveon sensor is a very minor one and the improvements in sharpness, enlargeability and realistic appearance of prints more than compensates the small amount of controllable stairstep aliasing. Unless you are pixel peeping with zoom it's rare to even see this type aliasing in prints.

In short, complaining about a Sigma SD14's "aliasing" is a solution in search of a problem.

Best regards,

Lin

Quote
If you like the look of aliasing artifacts or not, that's subjective. That they exist, and can be measured is not subjective but objective. Quite frankly, if you had a detailed enough resolution chart, you'd still be measuring resolution way beyond the pixels on your sensor if you don't stop when aliasing starts to occur. It's a joke to suggest that heavily aliased data is real resolution when it's an undesirable artifact. If you could keep your resolution as-is, but not have any aliasing, would that not be beneficial to your images?

Graeme
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Jonathan Wienke

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« Reply #74 on: October 25, 2007, 01:05:32 am »

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Hi Graeme,

This is where sampling theory and photographic reality collide. When I look at a b&w resolution chart at Nyquist a CFA sensor produces mush. When I shoot a landscape with grass, pine needles, leaves, etc., and enlarge a CFA print I get to a point where "mush" is very apparent. When nine converging lines on a resolution chart can no longer be resolved the AA filter produces a blob of indistinguishable grey plus color moire. In real-world photography this point is evident throughout when I reach the visible limits of resolution. These artifacts are far more objectionable to me than what you describe.

When my SD10 or SD14 stop resolving nine converging lines, I see five lines. Is this "real"? No - it's false detail but I still see "lines" not mush. Whether I see five blades of grass in my enlargement where there should be nine, or five pine needles where there should be nine on distant trees is largely unimportant as long as I still see something which resembles grass or pine needles or fur on wildlife (whose counting?). In my enlargements this false detail looks much more realistic than having an indistinguishable blob at the point of resolution exhaustion.

That's all well and good, but confusing aliasing artifacts with actual resolution, especially when publishing camera performance specifications, is deceptive and misleading. If you personally like the look of aliasing artifacts in your work, great. But not everyone shares your view.

Quote
Would I like more "resolution?" Sure. But no matter how much "resolution" I have, an antialiasing filter simply at some point in the equation produces moire and blur which I don't want in my enlargements.

I find it rather humorous that someone claiming to have a master's degree in physics thinks that an anti-aliasing filter causes moire. Its primary purpose is to prevent moire, a task which it does quite effectively. Does it introduce blur? Absolutely. But moire? Spare us.
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Ray

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« Reply #75 on: October 25, 2007, 08:31:58 am »

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LOL - what would you use for a lens? The 3.4 produces over 1500 lines, the 4.67 about 1760 so the 10 in that progression would produce around 3700 lines horiz and vertical - probably out resolve any current 35mm lenses??

Best regards,

Lin
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I can't follow the logic here, Lin. You can't have greater resolution than the number of pixels and the SD14 has only 4.67 million of them. If every one of them has a different value, that's a maximum of 4.67m different data points that comprise the image. The 40D could have 10m different data points.

The fact that the 40D cannot resolve up to the Nyquist limit is not the fault of the lens but is due to a combination of AA filter and pixel interpolation which is a design feature of the Bayer CFA. Interestingly, Phil Askey of dpreview has just completed a review of the 40D and comments that the images are a little softer than he'd like and suggests it's probably due to an AA filter which is too strong. Nevertheless, the 40D still manages an absolute resolution of 2200 lines horizontally. The 1Ds2 manages 2800 lines and I'm sure a 10mp foveon sensor could beat that, if noise is not too great.  
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Lin Evans

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« Reply #76 on: October 25, 2007, 08:51:38 am »

Jonathan,

No one said you had to "share my view" - and this is not about any confusion at all between "actual resolution and artifacts" - those are your misguided assumptions. Also you apparently don't understand the difference between color moire and luminance moire.

Who published performance specifications which are deceptive and misleading??? Are you pretending to know more about the performance of the Foveon processor than Carver Mead and Dick Lyons?  If so you are sadly mistaken.

Would you like for me to point out the quite obvious differences in the presence of color moire between same frames with the Foveon processor and a CFA processor. Would you then like to explain why there is no color moire with the Foveon? I don't "pretend" about anything, including my credentials, and I understand CFA technology very well. I clearly stated that the moire I'm referring to is beyond Nyquist but perhaps you missed that part. Also you apparently do not do enlarging and printing or you would already understand the effects of the combination of CFA sensor and AA filter designed to prevent moire below Nyquist limits combine to produce bad moire moire in that portion of unresolved data. Not only blurred but blurred with color moire. In copious enlargements this shows up as blotches of color smear making far worse artifacts than produced by the limited luminance moire and stairstep aliasing of the Foveon processor.

As I said earlier - no one is trying to force anyone to "like" aliasing or like Foveon. But what I am saying is that the resolution claimed for the Foveon processor is as accurate as any claimed for CFA sensors - anyone claiming otherwise is either ignorant of the facts or deliberately lying for some unknown reason.

Lin  

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That's all well and good, but confusing aliasing artifacts with actual resolution, especially when publishing camera performance specifications, is deceptive and misleading. If you personally like the look of aliasing artifacts in your work, great. But not everyone shares your view.
I find it rather humorous that someone claiming to have a master's degree in physics thinks that an anti-aliasing filter causes moire. Its primary purpose is to prevent moire, a task which it does quite effectively. Does it introduce blur? Absolutely. But moire? Spare us.
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John Sheehy

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« Reply #77 on: October 25, 2007, 08:56:53 am »

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When my SD10 or SD14 stop resolving nine converging lines, I see five lines. Is this "real"? No - it's false detail but I still see "lines" not mush. Whether I see five blades of grass in my enlargement where there should be nine, or five pine needles where there should be nine on distant trees is largely unimportant as long as I still see something which resembles grass or pine needles or fur on wildlife (whose counting?).[a href=\"index.php?act=findpost&pid=148533\"][{POST_SNAPBACK}][/a]

But they *don't* look like blades of grass or pine needles.  They look like Tetris pieces *colored* like blades of grass and pine needles.
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Lin Evans

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« Reply #78 on: October 25, 2007, 09:09:53 am »

Hi Ray,

Don't confuse optical resolution with display pixel count. The SD14 has 14 million sampling sites (photosites). The true correlation between optical resolution and pixels is with the number of sampling sites not with the number of display pixels.

The "measured" b&w resolution of the "3.4 megapixel" SD9/SD10 Foveon processor is identical or better than a six megapixel CFA sensor. The number of display pixels is irrelevant. Because CFA sensors have approximately an equal number of display pixels to the number of sampling sites this display pixel count is commonly, but improperly used in conjunction with the word "resolution". It's only because of this misconception that it's been widely accepted. Does an 8 megapixel cell phone have the same optical resolution as a Canon 30D? Why? They each produce a display with eight million pixels. The measured optical resolution if far different. So it follows that a CFA sensor can have less resolution than the theoretical limits imposed by the number of sampling sites but not more. This is also true of the Foveon processor. The Foveon processor is actually less efficient than the CFA processor of equal photosite count. The 10.3 million Foveon processor used in the SD9/SD10 only produces a measured count of 1550 lines horizontal/vertical (in reality, it can't be more than the vertical display pixel count of 1512 lines) but human visual acuity and standardized resolution chart print error account for the variance as observed by testing (Phil Askey on dPReview's figures). The same margin for error applies to all other cameras tested so if I accept their numbers then I must also accept the "measured" Foveon numbers of 1550 lines  vertical and horizontal. The "measured" color resolution is identical to the b&w resolution for this processor.

So there is no question that the Foveon processors produce the resolution measured as accurately as the CFA sensors. To assume otherwise is illogical.

A 10 megapixel (using a display pixel count) Foveon processor, if such a device could be built, would produce optical resolution of about 3700 lines (the 4.46 megapixel sensor produces 1760 lines). Remember, a Foveon processor with a 10 megapixel display would use slightly over 30m sampling sites.

Yes, the 40D has 10m sampling sites, the SD14 has 14m sampling sites. I agree with Phil - my 40D produces excellent color accuracy but noticeably softer images than my 1D Mark II or my 1DS. Also note that the resolution extinction figures are not great for the 40D. Compare them to the Sony Alpha 100 for instance. This is very likely an issue with AA filtering as Phil suggests.

For landscapes I very much prefer my D2XS or my Sigma SD14 to any of my Canon cameras including my 1DS which has a relatively "weak" AA filter (to use a term some dislike here - LOL).

Best regards,

Lin
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I can't follow the logic here, Lin. You can't have greater resolution than the number of pixels and the SD14 has only 4.67 million of them. If every one of them has a different value, that's a maximum of 4.67m different data points that comprise the image. The 40D could have 10m different data points.

The fact that the 40D cannot resolve up to the Nyquist limit is not the fault of the lens but is due to a combination of AA filter and pixel interpolation which is a design feature of the Bayer CFA. Interestingly, Phil Askey of dpreview has just completed a review of the 40D and comments that the images are a little softer than he'd like and suggests it's probably due to an AA filter which is too strong. Nevertheless, the 40D still manages an absolute resolution of 2200 lines horizontally. The 1Ds2 manages 2800 lines and I'm sure a 10mp foveon sensor could beat that, if noise is not too great. 
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« Last Edit: October 25, 2007, 09:21:42 am by Lin Evans »
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Graeme Nattress

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1Ds MKIII and Optical Low Pass filtering
« Reply #79 on: October 25, 2007, 09:40:28 am »

The issue with detail as it approaches the Nyquist limit is do you wish either of these two alternatives:

1) the detail blends out to nothing - a blur - the camera is saying "I don't know what's here"

or

2) the detail continues, but, it's not necessarily accurate - you eventually end up with a fizz of uncorrelated pixels, the camera is saying - "there's something there, but what I'm telling you is not correct - or it might be correct, but I'm not telling you which"

From my POV: 1) above is how I see the world.
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