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Author Topic: SIGMA DP-1  (Read 31525 times)
John Sheehy
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« Reply #80 on: February 27, 2008, 08:10:26 PM »
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Your scare is very weird, because it's not at all backed by the facts.

What scares me is exactly the contrary: artificial demand for more resolution and more megapixels (the more the better, isn't it? - marketing blurb).

That's not marketing blurb.  It's fact, easily demonstrated with cameras that do RAW, while the opposite has no proof at all, just a bunch of mantras, and bad conclusions drawn from the madness of the noise reduction race, and the high RAW-illiteracy rate of people who are otherwise generally on the up-and-up.  Back in the day, almost everyone I knew who was serious about photography knew about the darkroom; today, only a very small number of people even look at RAW data and try to work it themselves.  Then, they don't know what it is that they need to complain about, blaming the sensor for things done by software.

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Once upon a time a company called Fuji made a series a fine compact cameras around a 6.3 MP sensor (F10, F11, F20, F30). These were the first compact cameras that were able to produce decent images at 800 ISO.

Noise reduction, period.  No sensor that small has low noise images.  The Fuji 6.3MP sensor is average, in its class, perhaps below average.  It has a quantum efficiency a stop lower than the much-maligned 10MP Panasonic sensor in the FZ50, and slightly more read noise *per* pixel, with barely more than half of them.  Fuji, like Sigma, has created an impressionistic style of NR and conversion that has a strong following.

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They sadly were the last too.

They were the last, perhaps, to be rescued in the eyes of the optically naive by noise reduction at a 100% pixel view.  When you back away from individual trees, and look at the forest, then you will see why there is value in having assembled all these trees together.

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Fuji dropped this in under the pressure of the pixel-peeping crowds that always demand more pixels.

The term "Pixel Peeper", unfortunately, gets two groups of people lumped into it, with very different viewpoints.  I get called a pixel peeper because I study noise and signal to some degree, and it involves measurements with pixels, but I do not see the pixel as the determiner of image quality; it is only the quality of a spatial witness with a *varying* degree of accountability, depending on total pixel population in a displayed image, and the usage.  The person who complains about the MP race, in general, claiming that it leads to more noise, based on the individual pixel noise and/or softness is the true pixel peeper, IMO, at least as far as the negative connotations are concerned.

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The low-light capable F30 was replaced by a 10 MP F50 which is no better than the rest of the 10-12 MP compact cameras: useless over 400 ISO.

Do any of them output RAW?  Take the same shot on one and an S6500fd (which has the 6.3MP snesor and RAW), and link to the RAW files, and I will show you both, resampled to the same size, with no NR or other non-homogeneities.

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For the Foveon as for the other CMOS/CCD sensors (and as for silver halide emulsions...), there's a  trade-off between resolution and sensitivity.

Film is a *completely* different story than digital sensors.  Film is less sensitive when the grain is fine, and the developed grain expands very slowly, so it takes a lot of light to get a saturated capture (more original hots; less growth during devlelopment).  Digital has low sensitivity by being able to capture lots of photons per unit of area, but slowly.

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It's a good thing Foveon did not choose to increase resolution, because noise would be even more problematic. It is problematic enough to my taste.

Most of the noise that you see in Foveons is due to two things:

1) Problems with the color filtering method used leads to the blotches of green vs purple-blue in the shadows, and

2) Shot and read noises are magnified by the mathematical tricks used to get distinct, saturated hues out of the poorly separated RAW color channels.

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I clearly prefer crisp 8x12" prints (or slideshows) with low noise to accurate 1:1 luminance detail on my monitor and useless prints plagued with color noise.

What is "accurate 1:1 luminance detail"?

But big mosaics of noise are not a problem?  I can not simulate or replicate this alleged benefit you propose with low pixel density; the shot noise has the same energy, it's just a bit shallower, but bigger noise and image "grain".  The read noise usually has less energy with a higher pixel density.

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But John, you can rest assured that the vast majority still believes it's normal to have Christmas trees in any forest shot at 800 ISO.

I don't make any sense out of that statement.  Try paraphrasing it.

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And that you need to have enough resolution for 20x30" prints even if the lens resolves 30 lp/mm (24x36mm-equivalent) and less than thousand photographers on earth print a 20x30" each year.
[a href=\"index.php?act=findpost&pid=177783\"][{POST_SNAPBACK}][/a]

Resolution has nothing necessarily to do with print size.  High pixel density is also to get rid of artifact in the capture, and generally reduces image-level read noise, while maintaining image-level shot noise.  You can resample a 50MP image to 5MP, 4MP, 3MP, 12MP, etc, with a minimum of artifact.  A 6MP resampled to the same sizes will have more artifacts, and probably a bit more read noise.

You seem to completely miss the value and beauty of oversampling.
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Petia
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« Reply #81 on: February 28, 2008, 03:15:41 AM »
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Because silicon is a poor colour filter, the colours on a Foveon are somewhat guessed too....

Graeme
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Yes, that's right. Color balance with anything different than 5000K light seems tricky with the Foveon. A number of CCD dSLR have problems with deep purple hues. And the color spaces of our monitors and photographic papers are also limited... Think also about human perception and remember that three color channels are not always enough to accurately present the colored spectrum to the human eye!

There's no perfect technology in photography (or anywhere else), so all depends on the compromises one's willing (or not willing) to do.

To come back to the original topic, the Sigma DP-1, due next month, this kind of compact camera will be mostly judged on its ability to shoot in low light. That's the main advantage the large sensor is supposed to bring in (the other one --which shouldn't be neglected tough-- is that a small depth of field is possible with the Sigma and not with the standard digicams). The fact that the lens opens at f/4 is clearly a handicap, though there was little to do about this if the main objective was to keep the thing a compact camera (and not a bulky M8-sized one). So the sensor'd better properly handle high ISO (and that, by design, is not the forte of the Foveon). The images shot with the D14 at 800 ISO didn't impress me as far as noise is concerned. With the DP1 I'd like to see an improvement over the D14 at high sensitivity. Whether it'll be there or not is the question.
« Last Edit: February 28, 2008, 03:53:22 AM by Petia » Logged
Petia
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« Reply #82 on: February 28, 2008, 03:37:54 AM »
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You seem to completely miss the value and beauty of oversampling.

That's perfectly right. Explain me why Fuji was able to produce decent JPEG images at 800 ISO (and still usable ones at 1600) witha 6.3 MP sensor and is now unable to do it with a 10 MP sensor.
Their engineers have Alzeihmer's disease?
They decided that what you claim was an 'impressionistic' style -- and attracted followers, for sure -- was to be ditched because John Sheehy judged it looked bad?
They reasoned that Canon set the standard, and as it is crappy, they'd happily stick to it?

(BTW, as you didn't understand my comment: Xmas trees have nice colored garlands... normal fir trees have not -- at least in the forests I know)
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Petia
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« Reply #83 on: February 28, 2008, 04:20:16 AM »
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They were the last, perhaps, to be rescued in the eyes of the optically naive by noise reduction at a 100% pixel view. 

No. [I edited this after realizing the main difference between these cams]
Actually they were rescued by slight overexposure.

Compare this (Fuji F30, 800 ISO) with this (Canon SD950, 800 ISO) and or this (Fuji F50fd).

Look at the patterns in the black paper napkin, for example. The F30 gives far better results at 800 ISO. The downside is blown up highlights (white thread). In low light it is very rarely a problem, so there's the trick.
« Last Edit: February 28, 2008, 06:34:00 AM by Petia » Logged
John Sheehy
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« Reply #84 on: February 28, 2008, 08:36:27 AM »
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With the DP1 I'd like to see an improvement over the D14 at high sensitivity. Whether it'll be there or not is the question.
[a href=\"index.php?act=findpost&pid=177926\"][{POST_SNAPBACK}][/a]

They have exactly the same sensor; I don't think you can expect much difference, except in software NR in the JPEGs.
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Petia
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« Reply #85 on: February 29, 2008, 02:07:57 AM »
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There's something I don't get with the Fuji F30.
At 800 ISO, since the sensor has constant sensitivity, there's absolutely no chance of saturating the CCD wells. So the blown-up highlights come from their tone curve. This means that there's enough signal in the raw data to correctly reconstruct the shades (e.g. the dark napkin), and that in order to have enough contrast they sacrificed the highlights.
If John's theory is right (basically the law of large numbers + uncorrelated read noise, as far as I understand) why then isn't there enough signal in the 10 MP/12MP sensors in the same areas? If you look at the noise in these areas, you guess that even extra-smart processing won't recreate the patterns. It's not just a different tone curve. The F30 has more signal/noise in the shades. So?
« Last Edit: February 29, 2008, 06:24:56 AM by Petia » Logged
Petia
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« Reply #86 on: March 05, 2008, 05:34:25 AM »
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John's been strangely less eloquent lately...
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sojournerphoto
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« Reply #87 on: March 05, 2008, 07:11:21 AM »
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There's something I don't get with the Fuji F30.
At 800 ISO, since the sensor has constant sensitivity, there's absolutely no chance of saturating the CCD wells. So the blown-up highlights come from their tone curve. This means that there's enough signal in the raw data to correctly reconstruct the shades (e.g. the dark napkin), and that in order to have enough contrast they sacrificed the highlights.
If John's theory is right (basically the law of large numbers + uncorrelated read noise, as far as I understand) why then isn't there enough signal in the 10 MP/12MP sensors in the same areas? If you look at the noise in these areas, you guess that even extra-smart processing won't recreate the patterns. It's not just a different tone curve. The F30 has more signal/noise in the shades. So?
[a href=\"index.php?act=findpost&pid=178173\"][{POST_SNAPBACK}][/a]


I think the issue here is that the raw data is the ccd well votage (proportional to charge) multiplied by an amplifier before input to the adc. If the amplified signal exceeds the level required to give all 1s from teh adc then, regardless of the well saturation the highlights are clipped in the output.

Mike
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John Sheehy
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« Reply #88 on: March 05, 2008, 08:04:06 AM »
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There's something I don't get with the Fuji F30.
At 800 ISO, since the sensor has constant sensitivity, there's absolutely no chance of saturating the CCD wells.

It happens all the time with night shots with lights in them.

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So the blown-up highlights come from their tone curve. This means that there's enough signal in the raw data to correctly reconstruct the shades (e.g. the dark napkin), and that in order to have enough contrast they sacrificed the highlights.

In the vast majority of cameras, the sensor saturation level is only present in the lowest ISO, if at all.  It is the digitization process that normally clips data.  Many manufacturers clip the RAW data at their lowest ISO a bit short to keep the non-linear sensor saturation out of range.

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If John's theory is right (basically the law of large numbers + uncorrelated read noise, as far as I understand) why then isn't there enough signal in the 10 MP/12MP sensors in the same areas? If you look at the noise in these areas, you guess that even extra-smart processing won't recreate the patterns.

I haven't seen any compact Fuji 12MP RAWs.  It is often the case, however, that the higher MP cameras look worse at 100% pixel view, but not at the full image.

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It's not just a different tone curve. The F30 has more signal/noise in the shades. So?
[a href=\"index.php?act=findpost&pid=178173\"][{POST_SNAPBACK}][/a]

They don't have any special S/N in the shades; they have aggressive, cartoon-generating noise reduction.  There is no texture in fuji compact JPEGs in shadows or at high ISOs.
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John Sheehy
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« Reply #89 on: March 05, 2008, 08:07:10 AM »
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John's been strangely less eloquent lately...
[a href=\"index.php?act=findpost&pid=179252\"][{POST_SNAPBACK}][/a]

I read your post a few days ago, but it was a bit tangential to what I thought we were discussing, and your language really didn't suggest any precise questions; "So?", after some statements is not much of a question.  Ask better questions, and get quicker and better replies.
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Petia
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« Reply #90 on: March 05, 2008, 11:40:01 AM »
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I read your post a few days ago, but it was a bit tangential to what I thought we were discussing, and your language really didn't suggest any precise questions; "So?", after some statements is not much of a question.  Ask better questions, and get quicker and better replies.
[a href=\"index.php?act=findpost&pid=179283\"][{POST_SNAPBACK}][/a]


I'm referring to the images I linked to above. They are very interesting as we can precisely compare the performance of different cameras. There were some blown up highlights in the F30 output (e.g. white thread), and nice detail in the dark tones, e.g. in the black napkin.
This detail is absent from the Fuji F50 image (10 MP) and the Canon SD950 (12 MP). The patterns on the napkin are close to invisible.
Just explain me why Fuji engineers were not able to rescue decent signal in the dark tones with the 10 MP sensor while they could with the 6.3 MP one. OK, on the F50 they reduced the clipping in the highlights, but this could have been done while still getting as much signal in the shades (and only reducing contrast somewhere, for example in the shades...). In contrast (no pun intended) the Canon produces loads of noise in the black napkin, and the Fuji has erased all detail there.
If your oversampling theory is correct, the performance of the 10/12 MP should be at least on par with the 6.3 MP on these dark patterns.
My "so?" means: now up to you to try and justify your point that more pixels is better. I don't have access to the raw files, but we'll suppose that what Fuji electronics were able to do on them two years ago, they're still able to do now.

P.

PS: and please don't tell me the apparent F30 superiority at ISO 800 is all down to overaggressive NR. There's (far) less NR in the Canon image and it's pretty clear from that image that more NR would have cleared all the white patterns on the black napkin: that's actually what happens on the F50. In the less heavily processed Canon JPEGs the patterns are swamped by noise, and already close to invisible.

PPS: Look also at the reflection on the Wychwood ale bottle. On the F30 you can discern their setup between the softboxes, you can't on the Canon or F50. There's just a patch of gray divided by a fine black line. And by the way it's close to the center so lens quality differences should not matter much.
« Last Edit: March 05, 2008, 12:29:46 PM by Petia » Logged
John Sheehy
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« Reply #91 on: March 05, 2008, 10:27:25 PM »
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I'm referring to the images I linked to above. They are very interesting as we can precisely compare the performance of different cameras.

IMO, cameras that only outputs JPEGs that have extreme noise reduction are cartoon machines, not cameras.

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There were some blown up highlights in the F30 output (e.g. white thread), and nice detail in the dark tones, e.g. in the black napkin.

That's a clue to you right there; the F30 received better exposure, so naturally, the shadows are going to have less noise, and fall into a higher level with lower noise reduction.

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This detail is absent from the Fuji F50 image (10 MP) and the Canon SD950 (12 MP). The patterns on the napkin are close to invisible.
Just explain me why Fuji engineers were not able to rescue decent signal in the dark tones with the 10 MP sensor while they could with the 6.3 MP one. OK, on the F50 they reduced the clipping in the highlights, but this could have been done while still getting as much signal in the shades (and only reducing contrast somewhere, for example in the shades...).

No, it couldn't have been done that way.  If one is clipping and the other one isn't, then they received different relative (and probably absolute) exposures.  This is not an engineering issue per se; it is a programmer's issue, as the noise reduction (not just the noise) hides detail.

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In contrast (no pun intended) the Canon produces loads of noise in the black napkin, and the Fuji has erased all detail there.
If your oversampling theory is correct, the performance of the 10/12 MP should be at least on par with the 6.3 MP on these dark patterns.

Through this wreckage of noise reduction?  You must be kidding.

The fact is, every bright area on the F50 is clearly superior to the F30 in terms of resolution.  I can clearly read things on the labels in the F50 image that I struggle with or can't read at all in the F30 image.  Everything that isn't below a certain exposure level where the Fuji NR tries to remove all detail is more detailed in the F50.

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My "so?" means: now up to you to try and justify your point that more pixels is better. I don't have access to the raw files, but we'll suppose that what Fuji electronics were able to do on them two years ago, they're still able to do now.

We're looking at software as much as we are looking at electronics, and apparently through unequal exposure.

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P.

PS: and please don't tell me the apparent F30 superiority at ISO 800 is all down to overaggressive NR. There's (far) less NR in the Canon image and it's pretty clear from that image that more NR would have cleared all the white patterns on the black napkin: that's actually what happens on the F50. In the less heavily processed Canon JPEGs the patterns are swamped by noise, and already close to invisible.

Less heavily processed?  You must be kidding.  Have you ever, in your life, seen how much real noise is in RAW captures from compact's sensors?  The Canon is extremely noise-reduced too; it just doesn't have an edge-preserve priority like Fuji does.  *EVERY* compact sensor has chromatic noise when converted literally, even in the midtones at ISO 100.

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PPS: Look also at the reflection on the Wychwood ale bottle. On the F30 you can discern their setup between the softboxes, you can't on the Canon or F50. There's just a patch of gray divided by a fine black line. And by the way it's close to the center so lens quality differences should not matter much.
[a href=\"index.php?act=findpost&pid=179337\"][{POST_SNAPBACK}][/a]

I don't see any difference in the Fujis.  You're going to have to be more specific.  I'm not even going to look at the Canon.  The Canon is low-pass-filtered into oblivion.  I will never, ever again buy a small camera that doesn't do RAW.
« Last Edit: March 07, 2008, 08:11:15 AM by John Sheehy » Logged
amin
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« Reply #92 on: March 11, 2008, 11:25:09 AM »
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This has been a very interesting thread.  I am very familiar with the power of oversampling in practice.  That said, I have never been able to get high ISO images from any small sensor/high MP camera to have as much detail/noise as my old F30 (now sold) when considered at equal print sizes.  I can get close, but not all the way there.  I have seen John's example(s) of S6500 high ISO RAW images (same as F30 RAW), and I am unconvinced that on-board NR is the answer to the F30 capabilities.  As hellish as those RAWs look, they look better than downsampled images from high MP small sensor cameras.  I have tried RAW files from many high-end 10MP+ compacts, and after downsampling to 6MP with application of NR (Noise Ninja, Neat Image, Dfine, etc, I have tried many) at any step in the process, I cannot match the in-camera F30 result.  I can get much closer to that result than one might guess based on a misguided pixel-level review prior to downsampling, but I can't get all the way there.  Same goes for downsampling high ISO (3200+), NR-applied 1Ds III files to 12MP and comparing them to D3 files.  The D3 files still win, in terms of final detail/noise at an equal print/viewing size, in every comparison I have seen.  In the end, I understand why the high MP cameras should be able to match the result, but in practice I don't see it happening.  I'm guessing that John and others believe that it comes down to processing software and skills.  I'll believe that when I see a good, practical demonstration of it.

With regards to aliasing in the DP1 images, it is definitely there.  How bothersome one finds it is a personal issue.  All aspects including aliasing artifacts being considered, the DP1 samples I have seen are more pleasing to me, at moderate print sizes, than those of any other compact camera I have yet seen.
« Last Edit: March 11, 2008, 12:52:54 PM by amin » Logged

jing q
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« Reply #93 on: March 12, 2008, 02:13:03 AM »
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This has been a very interesting thread.  I am very familiar with the power of oversampling in practice.  That said, I have never been able to get high ISO images from any small sensor/high MP camera to have as much detail/noise as my old F30 (now sold) when considered at equal print sizes.  I can get close, but not all the way there.  I have seen John's example(s) of S6500 high ISO RAW images (same as F30 RAW), and I am unconvinced that on-board NR is the answer to the F30 capabilities.  As hellish as those RAWs look, they look better than downsampled images from high MP small sensor cameras.  I have tried RAW files from many high-end 10MP+ compacts, and after downsampling to 6MP with application of NR (Noise Ninja, Neat Image, Dfine, etc, I have tried many) at any step in the process, I cannot match the in-camera F30 result.  I can get much closer to that result than one might guess based on a misguided pixel-level review prior to downsampling, but I can't get all the way there.  Same goes for downsampling high ISO (3200+), NR-applied 1Ds III files to 12MP and comparing them to D3 files.  The D3 files still win, in terms of final detail/noise at an equal print/viewing size, in every comparison I have seen.  In the end, I understand why the high MP cameras should be able to match the result, but in practice I don't see it happening.  I'm guessing that John and others believe that it comes down to processing software and skills.  I'll believe that when I see a good, practical demonstration of it.

With regards to aliasing in the DP1 images, it is definitely there.  How bothersome one finds it is a personal issue.  All aspects including aliasing artifacts being considered, the DP1 samples I have seen are more pleasing to me, at moderate print sizes, than those of any other compact camera I have yet seen.
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I used to use a Fuji f10, then a Fuji f50fd, and now a Ricoh gx100.

I really miss my fuji f10. then f50fd was pretty horrible at low light.
I'm actually preparing to get another fuji f10 to do my work

All this talk about technical aspects sometimes overlooks a very basic emotional connection on : how does this picture look to me?

I've tried different cameras from Canon to Panasonic to Ricoh to Fuji and I have to say that the Fuji F10 produced for me a very photographic texture in its images which I managed to interpolate up to 33x44 inches with beautiful results and 8ft x 11ft with acceptable results (look here: [a href=\"http://superhyperreal.com/test/foodp2.html]http://superhyperreal.com/test/foodp2.html[/url] in print http://superhyperreal.com/NEWS/fcb6.jpg

People always talk about getting the effect later in post production but I treat cameras like lenses nowadays (different brands give different looks)
and frankly different cameras give different emotional connections (sometimes you just feel that using a certain camera for a certain type of work feels more..right. Same thing as you view the image on a screen)
I use my Ricoh for alot of general shots but I am looking to reuse my Fuji for my food shots because I can't get the "feeling" in the shots I am looking from my Ricoh for the food shots.
Conversely, you will see alot of people raving about their ricohs for certain kinds of work (street shooting, b/w) even though the IQ of the Ricoh is probably not the best.

Technical debate is great but this is just a little hello from the other side.
« Last Edit: March 12, 2008, 02:15:38 AM by jing q » Logged
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