1Ds MKIII and Optical Low Pass filtering

[Lin Evans]

Hi Graeme,

Yes, for some images and some purposes I agree; for others I disagree which makes it fortunate that we have choices.

Best regards,

Lin

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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[Lin Evans]

Do nine lines changing to five at Nyquist look like lines? Do they look like black and white "Tetris pieces?" Does the fact that a blade of grass is green suddenly make it different? Does the fact that a pine needle is green make it different?

Grass beyond Nyquist still resembles grass - pine needles beyond Nyquist still resemble pine needles and ferret fur beyond Nyquist still resembles ferret fur - LOL. You may see it quite differently and perhaps that's what happens when "you pixel peep" at levels never seen by one who views a print. My customers and users of the SD14 see it differently and isn't it a great thing that you have a choice?

Best regards,

Lin

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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[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.
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Lin,
Surely the SD14 has 4.67m sites with regard to spatial resolution. The other 9.3m are stacked underneath. Remove the CFA and AA filter from a 40D and you'd get a spectacularly high resolution B&W image, far sharper than anything the SD14 could produce. Is this not so?

[sojournerphoto]

Hi Mike,

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

Best regards,

Lin
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Excellent, that'll be 13.5Mp (40.5M sample sites) then. That ought to outresolve my 5D every which way.

Please can I have one with a canon lens mount and is compatibility (so I don't have to buy new glass), sensible shooting speed (3fps or better), decent autofocus and a sensible number of focus points, a focus screen I can use manually (a split image?) and low noise up to iso 400 at least (I can always use the 5D for higher iso work).

After that you can start work on the high resolution version.

Oh, please keep it nice guys - they are only tools.

Mike

[John Sheehy]

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.
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Only a zealot would accept 1550 lines in a camera that only has 1512.

You'll believe anything that supports your faith, won't you.

The smart thing would have been to ask, "what's wrong with this test?".

[Lin Evans]

If pigs had wings they "might" be able to fly.

Why don't you "try" removing the AA filter and CFA from a 40D and test it for yourself. Actually I'll tell you where you can have the AA filter removed for about $500.00. The point is you can't remove the CFA but you can remove the AA filter. And with it removed the answer is no, it doesn't produce spectacular "resolution" and it isn't a "sharper" image than the SD14 produces. It's been done with a number of Canon and Nikon CFA cameras.

We're not talking about theoretical constructs which don't exist, we're talking about real world photography with cameras which are available. Kodak made a nice six megapixel b&w pro-body camera with optional AA filtering. It had issues.

Best regards,

Lin

Lin,
Surely the SD14 has 4.67m sites with regard to spatial resolution. The other 9.3m are stacked underneath. Remove the CFA and AA filter from a 40D and you'd get a spectacularly high resolution B&W image, far sharper than anything the SD14 could produce. Is this not so?
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[Lin Evans]

Only a zealot would fail to read plain English which is ostensibly their "first language" and attempt such a pathetic distortion in their reply.

Only an armchair "expert" would continue to argue ceaselessly about the performance of a camera they have never held in their hand. It never ceases to amaze me how you have all the answers about something you have so little experience with.

Lin

Only a zealot would accept 1550 lines in a camera that only has 1512.

You'll believe anything that supports your faith, won't you.

The smart thing would have been to ask, "what's wrong with this test?".
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[John Sheehy]

Only a zealot would fail to read plain English which is ostensibly their "first language" and attempt such a pathetic distortion in their reply.

Only an armchair "expert" would continue to argue ceaselessly about the performance of a camera they have never held in their hand. It never ceases to amaze me how you have all the answers about something you have so little experience with.

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You don't have to hold a camera in your hands to see that it can't resolve more lines than it has, regardless of the definition of resolution.

You don't have to hold a camera in your hands to see nasty aliasing artifacts in the images.  The aliasing issues of a camera are not going to change because I am holding it.

You are coming across as a very irrational person, arguing against cold hard facts, like the role of alignment in the "resolution" of an aliasing sampler.  You have some kind of psychological or economic stake in the Sigma camera, or the images you've taken with it, and it has you writing some ridiculous things.

[Jonathan Wienke]

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.

I'm familiar with both, and an anti-aliasing filter prevents the occurrence of both. What's your point?

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'm well aware of the reasons why not, and why a Bayer-pattern sensor exhibits color moire if it has no AA filter. I've shot over 120,000 frames with various Canon DSLRs (10D, 1D-MkII, and 1Ds), and I have not yet encountered color moire in any of them.

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).

This is the deceptive and misleading stuff I'm talking about. It is impossible to capture actual image detail above the Nyquist limit. As has been pointed out by others already, at Nyquist you can either capture perfectly alternating black and white lines or 50% gray, depending on the alignment of the subject with the sensor. Above Nyquist, things get even worse, and counting the aliasing artifacts you get under such conditions as actual image detail in your "measurements" (as you and Phil are doing) is simply bullshit.

[Lin Evans]

O.K. Jonathan,

You're the "expert" here. I'm truly surprised that you are not making your living testing cameras because you obviously know more about them than the people who build them and the one's who do make their livings testing them. I'll have to recommend you to dPReview so you can help "tutor" them with their reviews. LOL...

Wow, I'm impressed that you have taken over 120,000 frames and never encountered color moire in any of them. I took well over 100,000 frames before you were born so you're not impressing me with your "experience". I also have taken many more than 1,000,000 frames with digital cameras including six Canon dSLR's, numerous Kodak Pro bodies, Sigma SD9, SD10 and SD14 and several Nikon Pro bodies. I have encountered color moire on numerous occasions so what you are demonstrating is the "lack" of your experience.

Thanks for the "lesson"....

Lin

I'm familiar with both, and an anti-aliasing filter prevents the occurrence of both. What's your point?
I'm well aware of the reasons why not, and why a Bayer-pattern sensor exhibits color moire if it has no AA filter. I've shot over 120,000 frames with various Canon DSLRs (10D, 1D-MkII, and 1Ds), and I have not yet encountered color moire in any of them.
This is the deceptive and misleading stuff I'm talking about. It is impossible to capture actual image detail above the Nyquist limit. As has been pointed out by others already, at Nyquist you can either capture perfectly alternating black and white lines or 50% gray, depending on the alignment of the subject with the sensor. Above Nyquist, things get even worse, and counting the aliasing artifacts you get under such conditions as actual image detail in your "measurements" (as you and Phil are doing) is simply bullshit.
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[Lin Evans]

Yep, I've got over $40,000 invested in Canon bodies and lenses, over $35,000 invested in Nikon and Kodak lenses and bodies and about $5,000 invested in Sigma so I have a huge economic investment in Sigma.

I use what works and I know what my images look like. You see "aliasing" everywhere you look. Fully half your posts on dPReview involve some discussion of aliasing and about 100% of your post concerning Sigma/Foveon concern your obsession with trying to convince people of the poor performance of the Sigma cameras. I'm not the one writing "ridiculous things" John, look in the mirror.

Nasty "aliasing" yep, that's your subjective opinion. It's not shared by the majority. In fact the "majority" of people listening to your constant obsessive/compulsive rhetoric about aliasing whom I've had conversations with think you are trolling the majority of the time.

You're all talk and no show, John. You talk the talk but you don't walk the walk. Were are your superior samples of CFA images with no aliasing. Where are your comparison shots of Foveon and CFA images? Were are "any" images you've taken??

I'll give you this, you really do like to talk - LOL

Lin

You don't have to hold a camera in your hands to see that it can't resolve more lines than it has, regardless of the definition of resolution.

You don't have to hold a camera in your hands to see nasty aliasing artifacts in the images.  The aliasing issues of a camera are not going to change because I am holding it.

You are coming across as a very irrational person, arguing against cold hard facts, like the role of alignment in the "resolution" of an aliasing sampler.  You have some kind of psychological or economic stake in the Sigma camera, or the images you've taken with it, and it has you writing some ridiculous things.
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[Lin Evans]

As far as I'm concerned - this discussion is over. I will not discuss more subjective issues with those who attempt to argue about images they have no experience with and who continually twist my words to make straw man arguments.

Use whichever camera pleases you and I'll do likewise.

Lin

[Jonathan Wienke]

Wow, I'm impressed that you have taken over 120,000 frames and never encountered color moire in any of them. I took well over 100,000 frames before you were born so you're not impressing me with your "experience". I also have taken many more than 1,000,000 frames with digital cameras including six Canon dSLR's, numerous Kodak Pro bodies, Sigma SD9, SD10 and SD14 and several Nikon Pro bodies. I have encountered color moire on numerous occasions so what you are demonstrating is the "lack" of your experience.

And how many of the cameras exhibiting moire had AA filters?

And with that resume, arguing that aliasing artifacts captured above Nyquist count as validly measured resolution is even more absurd. You should know better.

BTW, I was born in 1970. You exposed >100,000 frames before then?

As to comparisons, I've done them, both RAW-to-RAW and print to print. Foveon is noticeably better per-pixel than Bayer, but not to the extent that the Foveon kool-aid drinkers claim. When both are optimally sharpened, 3MP Foveon is about as good as 4-5MP Bayer. A well-executed 10D shot will beat a similarly well-done SD9 frame, but not by much. There's only so far Foveon's improved color resolution over Bayer can compensate for the spatial resolution disadvantage.

[ErikKaffehr]

Hi!

I have downloaded the PIMA/ISO 12233 testcharts for the Nikon D100 and the Sigma SD10 as JPEGS from the DPReview site and run them trough Imatest.

MTF 50 Figures (corrected):

Nikon D100: 1272 LW/PH
Sigma SD10: 1556 LW/PH

MTF at Nyquist limit:
Nikon: 0.147
Sigma: 0.534

I have no opinion on the figures. I have taken the images from the same test.

I have also run the same test on Canon 10D and got 1328 LW/PH at MTF 50. I never shoot JPEG myself, but JPEG is what I can find at DPReview.

Best regards

Erik

And how many of the cameras exhibiting moire had AA filters?

And with that resume, arguing that aliasing artifacts captured above Nyquist count as validly measured resolution is even more absurd. You should know better.

BTW, I was born in 1970. You exposed >100,000 frames before then?

As to comparisons, I've done them, both RAW-to-RAW and print to print. Foveon is noticeably better per-pixel than Bayer, but not to the extent that the Foveon kool-aid drinkers claim. When both are optimally sharpened, 3MP Foveon is about as good as 4-5MP Bayer. A well-executed 10D shot will beat a similarly well-done SD9 frame, but not by much. There's only so far Foveon's improved color resolution over Bayer can compensate for the spatial resolution disadvantage.
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[bjanes]

Hi!

I have downloaded the PIMA/ISO 12233 testcharts for the Nikon D100 and the Sigma SD10 as JPEGS from the DPReview site and run them trough Imatest.

MTF 50 Figures (corrected):

Nikon D100: 1272 LW/PH
Sigma SD10: 1556 LW/PH

MTF at Nyquist limit:
Nikon: 0.147
Sigma: 0.534

I have no opinion on the figures. I have taken the images from the same test.

I have also run the same test on Canon 10D and got 1328 LW/PH at MTF 50. I never shoot JPEG myself, but JPEG is what I can find at DPReview.

Best regards

Erik
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A MTF 50 of 1556 LP/PH is not attainable by a camera with a PH of 1512 pixels.

MTF at Nyquist of 0.534 indicates severe aliasing and possibly sharpening artifact if resharpening were applied. This is a know limitation of Imatest.

[Ray]

Why don't you "try" removing the AA filter and CFA from a 40D and test it for yourself.
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Lin,
With all respect, when I expressed that in the colloquial fashion, "If you remove the CFA and AA filter', I meant of course, if the CFA and AA filter is removed in the design stage. In other words, if Canon were to design a B&W only camera.

I'm addressing your statement that little purpose would be served in increasing the pixel count of the current 4.67mp of the SD14 because lenses are not good enough. This does not make sense to me because it's clear that real spatial resolution is limited to the 4.67m spatial photosites.

The fact that the Foveon sensor can 'make more' of those 4.67m pixels because they are real pixels which don't have to be interpolated is a separate issue from the resolving limits of lenses.

It seems clear to me that a B&W version of the 40D, without CFA and AA would deliver a much sharper and more detailed image that the SD14 could produce, and therefore a 10mp Foveon sensor ( with 30m collection points) would be required to match in color the resolution of the B&W designed 40D.

Are we now clear on that point?  

[ErikKaffehr]

Hi!

Thanks for pointing out this. I'm quite aware of both issues, but didn't feel competent enough to discuss. Wanted just to present the figures. Probably not a very good idea to present the data out of context.

Best regards
Erik

A MTF 50 of 1556 LP/PH is not attainable by a camera with a PH of 1512 pixels.

MTF at Nyquist of 0.534 indicates severe aliasing and possibly sharpening artifact if resharpening were applied. This is a know limitation of Imatest.
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[Jonathan Wienke]

I also have taken many more than 1,000,000 frames with digital cameras including six Canon dSLR's, numerous Kodak Pro bodies, Sigma SD9, SD10 and SD14 and several Nikon Pro bodies. I have encountered color moire on numerous occasions so what you are demonstrating is the "lack" of your experience.

Yep, I've got over $40,000 invested in Canon bodies and lenses, over $35,000 invested in Nikon and Kodak lenses and bodies and about $5,000 invested in Sigma so I have a huge economic investment in Sigma.

Rather curious statements, since your Canon image sample page only has D30 images, and your Nikon image sample page has only Coolpix 990 samples. And your Recent Images page only has 10D and 1D samples. If your web site is intended to impress your clients, you might want to let them know you have something better than the Canon 10D, 1D, and D30 (only one of which breaks the 6MP barrier) and a 3.3MP Nikon point-and-shoot, all of which are several generations old technologically. And your site makes no mention and has no samples of anything shot with any Kodak or other brand pro bodies.

If these cameras are the straw man you're arguing against WRT Bayer sensors, I'm NOT impressed.

[Lin Evans]

Jonathan,

Do you really have a point or are you simply showing more ignorance?

If I posted images from every digital camera I own and use or have owned and used over the years would that make you happy? LOL..

The site you apparently visited is a sample site with images from a few cameras which I find interesting. The CP990 and CP950 because of their use in digiscoping, the Sony DKC-ID1 and DSC-D700, a few Olympus models because of their place in history, the Canon D30 because it was Canon's first dSLR, the Canon 1D because it was Canon's first Pro-body. The Sigma SD9 and SD10 and Sony R1 because of their place in digital camera history.

I test cameras and peripherals for manufacturers and have done so for many, many years. I currently have over 30 digital cameras ranging from professional bodies to consumer level digicams. Some of the links are very old with images dating back to the 90's. I have used and discarded or sold another 30 or more over the years.

My customers don't even visit my samples site and could care less which equipment I use. They are only concerned with results and they pay me very well for giving them that.

In answer to your earlier question - yes, well over 100K images and well before 1970. In 1960 alone over 30K frames.

You appear to be a half way intelligent boy, if you would spend a bit of your time and intelligence actually "reading" what I said rather than trying to demonstrate the extent of your "knowledge" you would immediately see that you have misquoted me, constructed a straw man argument from your misquotes, and displayed your ignorance based on your misconceptions.

You are wrong about the comparative resolution of the SD9/SD10 viz CFA counterparts. Period...  Numerous testers who do this for a living disagree with your conclusions and have concrete "proof" of their findings.

Impress you? Don't flatter yourself. I could care less whether you are impressed. Color moire with cameras having AA filters? Yes, in every case. I won't waste my time producing a sample using my 1DS (since you appear to have this camera) photographing a herringbone suit coat to demonstrate just how "easy" it is to produce color moire with the 1DS. Making statements like you made (120,000 frames - no moire) simply tells anyone with any true experience with this issue that you either have no clue or you have never shot subjects prone to moire. Some software companies have made a fortune creating software to ameliorate color moire for cameras with AA filters as well as for cameras without AA filters.

Don't bother replying unless you simply want to attempt to impress others with your vast knowledge of optical physics because this is my last comment on this issue.

Concerning the Foveon processor you simply have no clue.

Lin

Rather curious statements, since your Canon image sample page only has D30 images, and your Nikon image sample page has only Coolpix 990 samples. And your Recent Images page only has 10D and 1D samples. If your web site is intended to impress your clients, you might want to let them know you have something better than the Canon 10D, 1D, and D30 (only one of which breaks the 6MP barrier) and a 3.3MP Nikon point-and-shoot, all of which are several generations old technologically. And your site makes no mention and has no samples of anything shot with any Kodak or other brand pro bodies.

If these cameras are the straw man you're arguing against WRT Bayer sensors, I'm NOT impressed.
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[Jonathan Wienke]

Jonathan,

Do you really have a point or are you simply showing more ignorance?

Just this:
Spatial aliasing artifacts are not the same as actual resolution above Nyquist. If you want to claim that Foveon caputes detail up to Nyquist, fine. I agree that it does. But claiming that any sampled system can capture valid data beyond Nyquist is disingenuous. If you have a mathematically demonstrable method for reliably and predictably capturing >Nyquist frequencies with a sampled system, you should patent it and make a huge amount of money not only in digital imaging, but digital audio as well. Otherwise, let's quit defending flawed testing methodologies that fail to distinguish between actual captured image detail and aliasing artifacts and claiming that said test methods yield accurate performance measurements. Not everyone agrees that aliasing artifacts are desirable, especially in the world of digital audio.

I did a comparison a few years ago between the SD9 and the 10D that compared RAW images and prints, and concluded that the 10D had a slight edge on the SD9 in overall detail and print sharpness. The 10D was softer straight out of the RAW converter, but could be sharpened to about 70% of the SD9's per-pixel image quality with deconvolution-based capture sharpening (I used Focus Magic as opposed to USM). I don't have access to the files and prints; they're in storage in the states right now. Can you point me to a comparison that shows a Foveon image that is superior to a Bayer image with more than twice the pixel count? I'd be happy to change my opinion if you can show me some evidence.