October 20, 2014, 01:57:44 PM

Author Topic: Canon's Medium Format  (Read 22610 times)

vscd

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Re: Canon's Medium Format
« Reply #135 on: March 31, 2014, 04:40:07 AM »
@jrista

Yepp, but one *large* advantage of a foveon is that you don't need a Zeiss Otus to get your 36MP Sensor served. "Normal" sharp lenses, even customer-ones, get 15MP Pixels without problems... so the whole, or at least most better L, Canon Lense Lineup would be able to outperform the D800E.

Of course the layers constrict the light... until someone invents something new and proves the old wrong.
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Re: Canon's Medium Format
« Reply #135 on: March 31, 2014, 04:40:07 AM »

CarlTN

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Re: Canon's Medium Format
« Reply #136 on: March 31, 2014, 06:06:44 PM »
@jrista

Yepp, but one *large* advantage of a foveon is that you don't need a Zeiss Otus to get your 36MP Sensor served. "Normal" sharp lenses, even customer-ones, get 15MP Pixels without problems... so the whole, or at least most better L, Canon Lense Lineup would be able to outperform the D800E.

Of course the layers constrict the light... until someone invents something new and proves the old wrong.

Have you seen the new DP2?  They claim up to 39 MP...

vscd

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Re: Canon's Medium Format
« Reply #137 on: April 01, 2014, 04:22:49 AM »
Quote
Have you seen the new DP2?  They claim up to 39 MP...

I have and I'm waiting for the reviews, I think I may get one if the results are good. 39 MP are realistic... of course you just have to get rid of the context "pixels" just by x/y Resolution. The Details of a FoveOn (@lowISO) are outstanding above a Nikon or even a Pentax 645D!

F.e. (picture from dpreview.com):


This was the first sensor which really catched my attention after buying my 5D back then. Everything else is just "evolution" here and there, half a stop more Dynamic, more resolution, ISO25600. Hooray, you invented the holy grail. Nikon bla, Canon bla... everything no real leap. A 5D is still awesome and able to serve my needs. The sigma is again something worth time spending with.
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CarlTN

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Re: Canon's Medium Format
« Reply #138 on: April 01, 2014, 05:53:23 AM »
Quote
Have you seen the new DP2?  They claim up to 39 MP...

I have and I'm waiting for the reviews, I think I may get one if the results are good. 39 MP are realistic... of course you just have to get rid of the context "pixels" just by x/y Resolution. The Details of a FoveOn (@lowISO) are outstanding above a Nikon or even a Pentax 645D!

F.e. (picture from dpreview.com):


This was the first sensor which really catched my attention after buying my 5D back then. Everything else is just "evolution" here and there, half a stop more Dynamic, more resolution, ISO25600. Hooray, you invented the holy grail. Nikon bla, Canon bla... everything no real leap. A 5D is still awesome and able to serve my needs. The sigma is again something worth time spending with.

Their stated pixel dimensions don't make sense, unless the sensor is not a 3:2 aspect.  I enjoyed the generation 1 Foveon a lot.  Even though it was only 4.6 MP, it easily scaled to 25 MP, still looked sharp at that resolution on prints at 300 ppi.  TDP and others reckoned the actual resolution was 14 MP, but I feel like it was a bit more (at least below ISO 200).

In the future I hope Sigma make a full frame DSLR with a foveon sensor, WITH A CANON EF MOUNT...rather than a Sigma mount.  That way it could use all lenses, rather than only Sigma's.  And if they make another crop sensor DSLR first, with the new DP series sensor, I hope it too comes with an EF mount.  More people would buy Sigma's cameras if they at least offered having an EF mount as an option.

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Re: Canon's Medium Format
« Reply #139 on: April 01, 2014, 04:50:11 PM »
@jrista

Yepp, but one *large* advantage of a foveon is that you don't need a Zeiss Otus to get your 36MP Sensor served. "Normal" sharp lenses, even customer-ones, get 15MP Pixels without problems... so the whole, or at least most better L, Canon Lense Lineup would be able to outperform the D800E.

Of course the layers constrict the light... until someone invents something new and proves the old wrong.

It's not just the layers or well depth that constricts the light. If you look at the Foveon design (and, for that matter, Canon's own layered sensor patents), they have a LOT more activate and readout wiring per pixel. It's really complicated stuff, which further restricts the actual light-sensitive photodiode area.

The whole "eqivalent megapixels" deal that Sigma uses is also very misleading. Currently, today, megapixel counts are based on output image widthxheight. A 15mp Sigma Foveon is 15mp, in terms of actual megapixels stored in the output JPED image or a JPEG that you can create from RAW. It may have 45 million photodiodes, but that is not the same as megapixels, and I really wish Sigma would stop being so misleading.

I like the Foveon sensor design, it has SO much potential. It's just in the wrong hands with Sigma...they can't seem to develop it and bring it to bear on the market in a form that would make it a truly viable competitor with higher MP bayer type sensors. I think there are some innovations that have been developed for video sensor technology that could greatly increase the transparency of the silicon that surrounds the layered photodiodes and improve Q.E., reduce noise, improve dynamic range, etc. I've been hoping that Canon was working with some of those technologies on their own layered sensor design.

I would also dispute the whole "need for high resolution lenses" argument. Output resolution, in spatial terms, is the convolution of both sensor and lens resolution...AND, a most important point here, is LIMITED by the LEAST common denominator. The Sigma DP2, for example, is a 4.7 megapixel camera!!! Spatially, that is VERY low resolution. It is not a 15mp camera. It has richer, more complete color information per pixel, however from a luminance standpoint, it's luminance resolution is extremely low. It's pixel pitch is 7.85µm. Those are nice, big pixels, however because of the wiring requirements, the photodiode area is a lot smaller than 7.85µm (I don't know exactly off the top of my head...I would have to find the patents again...but I'd say that at least a third of the area is lost, so maybe around 6.3µm, which is about the same as the 5D III.)

The biggest benefit for the Foveon is the lack of an AA filter. You still experience moire, but because full color information is gathered at each pixel, you only have monochrome moire. Mono moire in most "natural" cases in photography is often not that bad. The lack of an AA filter makes it SHARPER, but it does not really increase the resolution of the sensor. This is very obvious from VCD's comment:

Quote
Have you seen the new DP2?  They claim up to 39 MP...

I have and I'm waiting for the reviews, I think I may get one if the results are good. 39 MP are realistic... of course you just have to get rid of the context "pixels" just by x/y Resolution. The Details of a FoveOn (@lowISO) are outstanding above a Nikon or even a Pentax 645D!

F.e. (picture from dpreview.com):


This was the first sensor which really catched my attention after buying my 5D back then. Everything else is just "evolution" here and there, half a stop more Dynamic, more resolution, ISO25600. Hooray, you invented the holy grail. Nikon bla, Canon bla... everything no real leap. A 5D is still awesome and able to serve my needs. The sigma is again something worth time spending with.

I think VCD has radically misinterpreted this comparison. The Sigma SD1 does not have anything even remotely close to the same resolution as the D800 or 645D. It isn't even a contest. The Sigma SD1 appears to be sharper...but that is only in a non-normalized comparison like this, and sharpness alone does not translate into more resolution. If one were to downsample the D800 and 645D images to the same dimensions as the SD1 image, they would likely TROUNCE the SD1. They have significantly more information in total, and while they may seem slightly soft at the pixel level, on a normalized basis, all that extra information gets interpolated into fewer, but much more accurate, sharper, richer and less noisy pixels.

Furthermore, the D800 and 645D both have more information to start with. They are resolving details that are not even present in the SD1 image at all, despite it's sharpness. Even if those details aren't as crisp as the LESSER details of the SD1, it's still more detail. A light sharpening filter can deal with the softness in a few seconds, and then the SD1 is at a real disadvantage. You can sharpen the SD1 image in post to your heart's content...that will never create information that was never there to begin with, and since it's already sharp, your probably doing yourself a disservice by sharpening SD1 images.

So arguing that the DP2, which itself is still just a 4.7mp camera (or even the SD1, which is a much higher resolution Foveon), is potentially equivalent to a 39mp camera, is gravely missing the point of having a truly higher resolution sensor (in luminance terms...luminace is where detail comes from, color CAN be of much lower spatial resolution so long as your luminance information is high...as a matter of fact, this is actually a standard practice in astrophotography, to image at high resolution in luminance, then when you switch to RGB filters, you bin 2x2 or 3x3, which increases your sensitivity, and reduces your resolution by 4x or 9x...and your never the wiser when looking at the final blended result). It buys into the very misleading hype that Sigma spews, which I believe is ultimately, in the long term, going to damage their reputation and hurt Foveon (because as more people try to produce images with a 4.7mp or 15mp Foveon sensor that compare to even the regular old D800, let alone the D800E or the 645D, and realize they simply cannot...they are either going to ditch Foveon and go back to bayer type sensors, or they are going to begin badmouthing Foveon.)

CarlTN

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Re: Canon's Medium Format
« Reply #140 on: April 02, 2014, 02:23:43 AM »
So arguing that the DP2, which itself is still just a 4.7mp camera (or even the SD1, which is a much higher resolution Foveon), is potentially equivalent to a 39mp camera, is gravely missing the point of having a truly higher resolution sensor (in luminance terms...luminace is where detail comes from, color CAN be of much lower spatial resolution so long as your luminance information is high...as a matter of fact, this is actually a standard practice in astrophotography, to image at high resolution in luminance, then when you switch to RGB filters, you bin 2x2 or 3x3, which increases your sensitivity, and reduces your resolution by 4x or 9x...and your never the wiser when looking at the final blended result). It buys into the very misleading hype that Sigma spews, which I believe is ultimately, in the long term, going to damage their reputation and hurt Foveon (because as more people try to produce images with a 4.7mp or 15mp Foveon sensor that compare to even the regular old D800, let alone the D800E or the 645D, and realize they simply cannot...they are either going to ditch Foveon and go back to bayer type sensors, or they are going to begin badmouthing Foveon.)

Nobody said the first generation Foveon sensor is equal to 39 MP.  Jrista, again you learn about what you're interested in, but this leaves a lot of facts for you to miss. 

When I mentioned the "new DP2", I was referring to this...it's called the Quattro.

http://www.sigma-global.com/en/cameras/dp-series/

...And it's most definitely more resolution than the SD-1...it's a new sensor with more pixels.  Just exactly how many pixels it is, is kind of unclear.  I think Sigma don't mind that it is unclear...lol.  The actual pixel dimensions of the RAW image, might be 19 MP, or might be more.  For some reason it can produce JPEGs that are 7680 x 5120 = 38.3 MP. 

To argue about what outresolves what, on such a new product, is a waste of time in any case.

I try to speak about what I have had experience with.  I've owned the original DP2, and it most certainly had more resolution than its native 4.6 MP image.  As I said, it could easily scale to about 25 MP, and still look sharp enough to me for a print at 300 ppi. 

So there's no reason to start bashing Sigma, and talking about what "TROUNCES" what.  Nobody thinks a crop sensor is ever going to be "better" than a full frame sensor...other than you and your 7D :P.  Everybody knows nothing compares to the mighty 7D!




vscd

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Re: Canon's Medium Format
« Reply #141 on: April 02, 2014, 06:31:13 AM »
@jrista

Yepp, you mixed some things. The first FoveOns were 5Mpixel on three Layers, which (could) be summed up to 15MPixel. The next generation was the Merrill, where about 15MPixel on 3 Layers can be counted to 45MPixel. The new Quatto Design ist again 3layered, but just the blue one get's 19MPixel, where the other 2 are just about 5 MPixel each. Now happy counting ;)

At the End, the results are crucial.

Quote
It may have 45 million photodiodes, but that is not the same as megapixels, and I really wish Sigma would stop being so misleading.

This is of course confusing, but it's not a lie, because... let's define a pixel. You refer to it as a Pixel is the Picture which comes out from the cam. The Pixels from the Sensor are something different... you could also count each layer as a single Pixel, because it has an own wired output and the information is capsulated within this *single* Lighttrap. Remember the Nikon D2X (or was it the D1x?), there the Pixels were halfsized, so what do you count? ;) It's some kind of definition. The Sigmapeople have the same "problem" as Intel had 10 years ago... recognizing that Megahertz has nothing to do with speed, but the people don't know this. So you have to catch them with Numbers they understand.

Quote
Furthermore, the D800 and 645D both have more information to start with. They are resolving details that are not even present in the SD1 image at all, despite it's sharpness

No, they DON'T, that's what the image should have told you. I could resize the Sigma-Picture 4 Times and have more resolution, but not more information.

Quote
A light sharpening filter can deal with the softness in a few seconds, and then the SD1 is at a real disadvantage.

Please try and proove me wrong, the RAW-Data is available for download @dpreview.com  ;)

By the way, the Size of the photodiodes are of course really important, especially on lowlight, but the technology solves some of the problems. On the paper no one could beat my old 5D with ca. 8.2 Microns, but in reality your 1DX would run circles around it  8)
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Re: Canon's Medium Format
« Reply #141 on: April 02, 2014, 06:31:13 AM »

Ellen Schmidtee

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Re: Canon's Medium Format
« Reply #142 on: April 02, 2014, 08:41:44 AM »
The whole "eqivalent megapixels" deal that Sigma uses is also very misleading. Currently, today, megapixel counts are based on output image widthxheight. A 15mp Sigma Foveon is 15mp, in terms of actual megapixels stored in the output JPED image or a JPEG that you can create from RAW. It may have 45 million photodiodes, but that is not the same as megapixels, and I really wish Sigma would stop being so misleading.

No more misleading than stating a sensor has so many megapixels, when each photodiode samples one color, and the other two are interpolated in the JPEG.

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Re: Canon's Medium Format
« Reply #143 on: April 02, 2014, 08:54:38 AM »
The whole "eqivalent megapixels" deal that Sigma uses is also very misleading. Currently, today, megapixel counts are based on output image widthxheight. A 15mp Sigma Foveon is 15mp, in terms of actual megapixels stored in the output JPED image or a JPEG that you can create from RAW. It may have 45 million photodiodes, but that is not the same as megapixels, and I really wish Sigma would stop being so misleading.

No more misleading than stating a sensor has so many megapixels, when each photodiode samples one color, and the other two are interpolated in the JPEG.

Well not really. Each pixel has its own brightness level, so resolves its own detail, the colour of each pixel is a result of the surounding pixels, but not the brightness. The MP count of a Bayer arrayed sensor is a truthful reflection of the actual individual brightness measurements.

In essence, the colour might be off but the detail isn't, just look at the Monochrome Leica to realise that.
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Re: Canon's Medium Format
« Reply #144 on: April 02, 2014, 10:24:00 AM »
...let's define a pixel. You refer to it as a Pixel is the Picture which comes out from the cam. The Pixels from the Sensor are something different... you could also count each layer as a single Pixel

No more misleading than stating a sensor has so many megapixels, when each photodiode samples one color, and the other two are interpolated in the JPEG.

A pixel is best defined as a unit of spatial information.  Interpolation of color information does not change the underlying luminance or spatial information.  Counting multiple layers of a given spatial element as separate pixels is misleading (intentionally so, on Sigma's part).  The Sigma DP2 has a 4.6 MP sensor, not a 14 MP sensor.  One could argue that Bayer-type sensors do not deliver their full potential spatial resolution due to the blurring from the OLPF (AA filter).  However, with a properly designed OLPF (one that blurs spatial frequencies above the Nyquist limit for the underlying CMOS sensor) and proper application of sharpening in post-processing, there's no significant loss of spatial resolution from the OLPF (as shown by comparisons of D800E images to properly-sharpened D800 images, although technically the D800E does have an OLPF, just one that's designed not to introduce blur).

Some of my Zeiss microscope cameras use an older Sony 1.3 MP CCD sensor with no microlenses.  Unlike dSLR sensors, the Bayer mask is physically separate from the CCD.  The camera can take a 'standard' image, analogous to a dSLR picture, that delivers a 1.3 MP image with the color values interpolated across neighboring pixels.  The camera can also piezoelectrically move the CCD in 1-pixel increments, such that with three successive images each pixel is directly capturing R/G/B and no color interpolation is needed…that means the color is more accurate, but it's still just a 1.3 MP image.  Interestingly, the camera can also move the CCD in sub-pixel increments as either a 2x2 or a 3x3 array within the space of a single pixel – that results in an increase in real spatial resolution, producing a 5 MP or a 13 MP image, respectively, from that 1.3 MP sensor.  Of course, gapless microlenses would obviate the benefit of moving the sensor, and the process only works with static subjects (fixed specimens), since a 13 MP image without color interpolation means capturing 27 separate images and merging them spatially and chromatically.
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jrista

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Re: Canon's Medium Format
« Reply #145 on: April 02, 2014, 04:55:03 PM »
So arguing that the DP2, which itself is still just a 4.7mp camera (or even the SD1, which is a much higher resolution Foveon), is potentially equivalent to a 39mp camera, is gravely missing the point of having a truly higher resolution sensor (in luminance terms...luminace is where detail comes from, color CAN be of much lower spatial resolution so long as your luminance information is high...as a matter of fact, this is actually a standard practice in astrophotography, to image at high resolution in luminance, then when you switch to RGB filters, you bin 2x2 or 3x3, which increases your sensitivity, and reduces your resolution by 4x or 9x...and your never the wiser when looking at the final blended result). It buys into the very misleading hype that Sigma spews, which I believe is ultimately, in the long term, going to damage their reputation and hurt Foveon (because as more people try to produce images with a 4.7mp or 15mp Foveon sensor that compare to even the regular old D800, let alone the D800E or the 645D, and realize they simply cannot...they are either going to ditch Foveon and go back to bayer type sensors, or they are going to begin badmouthing Foveon.)

Nobody said the first generation Foveon sensor is equal to 39 MP.  Jrista, again you learn about what you're interested in, but this leaves a lot of facts for you to miss. 

When I mentioned the "new DP2", I was referring to this...it's called the Quattro.

http://www.sigma-global.com/en/cameras/dp-series/

...And it's most definitely more resolution than the SD-1...it's a new sensor with more pixels.  Just exactly how many pixels it is, is kind of unclear.  I think Sigma don't mind that it is unclear...lol.  The actual pixel dimensions of the RAW image, might be 19 MP, or might be more.  For some reason it can produce JPEGs that are 7680 x 5120 = 38.3 MP. 

To argue about what outresolves what, on such a new product, is a waste of time in any case.

I try to speak about what I have had experience with.  I've owned the original DP2, and it most certainly had more resolution than its native 4.6 MP image.  As I said, it could easily scale to about 25 MP, and still look sharp enough to me for a print at 300 ppi. 

So there's no reason to start bashing Sigma, and talking about what "TROUNCES" what.  Nobody thinks a crop sensor is ever going to be "better" than a full frame sensor...other than you and your 7D :P.  Everybody knows nothing compares to the mighty 7D!

I don't know where you guys are getting your info. On your own site, the DP2 is listed as having 29mp effective (non-masked) "photo detectors", which are the same thing as a photodiode. From the dp-series link:

Color Photo Detectors    Total Pixels: Approx.33MP, Effective Pixels: Approx.29MP

That is 29 million PHOTODIODES. That means, from a SPATIAL standpoint (actual resolving power), you have 29/3 million PIXELS (actual square areas on the sensor that are light sensitive), or 9.7mp. The DP2 that you are referring to is a TEN MEGAPIXEL sensor. Not only that, it is a 10mp APS-C sized sensor, so were talking pretty small pixels.

I'm sorry, but it doesn't matter how good those pixels are...there is no way, physically, that they could ever compare to the 36.3mp of a D800 nor the 40mp of the 645D. Spatially, from a luminance (detail) perspective, there is no loss of data or resolution in a bayer array. There is only, ONLY, a loss of color data or color spatial resolution. The loss of spatial color detail is a bit of a detractor for bayer type sensors, it hurts their color fidelity a little bit, however it is not enough of a detractor to warrant calling a 9.7mp Foveon as good as a 39mp bayer. The FULL detail luminance from a bayer is more than enough to offset the loss in color detail.

Neuro has explained how a properly designed OLPF (which is usually the case these days, even leaning towards the slightly weak side more often than not), despite blurring high frequency data, is not a huge detractor for bayer sensors as OLPF's blur predictably and consistently across the area of the sensor, meaning a light sharpening filter in post usually reverses the softening impact of an OLPF.

The whole "eqivalent megapixels" deal that Sigma uses is also very misleading. Currently, today, megapixel counts are based on output image widthxheight. A 15mp Sigma Foveon is 15mp, in terms of actual megapixels stored in the output JPED image or a JPEG that you can create from RAW. It may have 45 million photodiodes, but that is not the same as megapixels, and I really wish Sigma would stop being so misleading.

No more misleading than stating a sensor has so many megapixels, when each photodiode samples one color, and the other two are interpolated in the JPEG.

Your misunderstanding. Every bayer pixel may have only one color, but regardless of color, every pixel receives "light". This is why the spatial resolution of a bayer sensor is so high, and why a D800 is capable of resolving so much detail. If you convert a bayer sensor's data to monochrome, you effectively have just the full detail luminance. Advanced demosaicing algorithms like AHDD are explicitly designed to preserve as much luminance detail as possible, while effectively distributing color data to avoid mazing artifacts and other demosiacing quirks. A bayer sensor needs no interpolation from a luminance standpoint, they only need interpolation from a color standpoint. Bayer sensors have nearly their full resolution in terms of luminance, and since luminance is really what carries your fine detail, they DO have FAR more resolution than any Foveon on the market today, including the SD1.

This isn't missleading, it's how the physics and mathematics of interpolation work. Interpolation algorithms like AHDD are actually capable of producing crisper, smoother, sharper results with a bayer than your standard, basic demosaicing algorithm, and AHDD is pretty ubiquitous these days (LR/ACR use it, Adobe Aperture uses it, and it's a demosaicing option in most Linux RAW editors like RawThearapy and Darktable.) AHDD is even used in lower level tools, often used for astrophotography, like DeepSpaceStacker, Iris, and PixInsight.

The only loss with a bayer type sensor is in terms of color spatial resolution and color fidelity. The most obvious of those is really color fidelity, as when chrominance is blended with luminance, our eyes can't really tell the difference, or at least the difference is small enough that it isn't an issue unless you are directly comparing, side-by-side, a Foveon and Bayer image with the same image dimensions (in other words, if you had a 10mp bayer and a 10mp Foveon, then you would be able to tell that the Foveon had slightly better color microcontrast and better color fidelity...however when comparing a 35 or 40mp bayer to a 10mp Foveon, the only visible difference MIGHT be sharpness...that would depend on the strength or presence of an AA filter.)

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Re: Canon's Medium Format
« Reply #146 on: April 02, 2014, 05:04:53 PM »
If you convert a bayer sensor's data to monochrome, you effectively have just the full detail luminance.

If you can just expand on that a little Jon. When you say 'you' are you referring to the manufacturers setting it up this way ( like the Leica monochrome), or the user converting the RAW to B&W ?

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Re: Canon's Medium Format
« Reply #147 on: April 02, 2014, 05:38:58 PM »
@jrista

Yepp, you mixed some things. The first FoveOns were 5Mpixel on three Layers, which (could) be summed up to 15MPixel. The next generation was the Merrill, where about 15MPixel on 3 Layers can be counted to 45MPixel. The new Quatto Design ist again 3layered, but just the blue one get's 19MPixel, where the other 2 are just about 5 MPixel each. Now happy counting ;)

At the End, the results are crucial.

Actually, the results aren't all that crucial. You don't have a 19mp sensor just because the blues are higher resolution. You get something around the average of the spatial resolutions of all three colors. Red has the lowest weight, green actually has the highest weight because it is where the bulk of light entering a camera usually comes from. Blue has the second highest weight. You can increase luminance detail in blue, but since blue is inherently a lesser component of visible light, and since our eyes are less sensitive to blues, green dominates. The bulk of the luminance detail is going to come from green, and since that is a lower resolution than the blues, you don't have a 20mp sensor. If you just take the averages, you have 9.7mp. You might have somewhere between 10-15mp, depending on exactly how the Foveon color information is processed and, for lack of a better word, interpolated, to produce a final image. Either way, you still aren't getting any more spatial resolution than the SD1 had years ago, and honestly I'd prefer the SD1 design, rather than the quattro design (becase at least with the SD1, your spatial resolution was exact, not some blend of higher and lower frequency pixel spacing.)

Sigma is still being very misleading by saying that you get 39mp. They are working some quirky imaginary mathematical magic as well, because assuming you just added up the resolutions of each pixel, you get 19.6+4.9+4.9, which is 29.4mp. How they get to 39mp is beyond me, however I suspect they are using some arbitrary means of measuring an upscaled image in relation to bayer images like they have done in the past. Simple fact of the matter is, upscaling and bayer interpolation (especially with AHDD) are NOT the same thing, and do NOT produce the same results. Sigma is probably comparing images demosaiced with your standard 2x2 intersection-based demosaicing to upscaled Foveon images, which is intentionally putting bayer at a significant disadvantage that ignores the most common and effective means of demosaicing.

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It may have 45 million photodiodes, but that is not the same as megapixels, and I really wish Sigma would stop being so misleading.

This is of course confusing, but it's not a lie, because... let's define a pixel. You refer to it as a Pixel is the Picture which comes out from the cam. The Pixels from the Sensor are something different... you could also count each layer as a single Pixel, because it has an own wired output and the information is capsulated within this *single* Lighttrap. Remember the Nikon D2X (or was it the D1x?), there the Pixels were halfsized, so what do you count? ;) It's some kind of definition. The Sigmapeople have the same "problem" as Intel had 10 years ago... recognizing that Megahertz has nothing to do with speed, but the people don't know this. So you have to catch them with Numbers they understand.

A pixel is a spatial measure, two dimensional, not three dimensional. You can define pixels in many ways, however as far as bayer is concerned, it's all the same. You can measure the individual r, g, and b pixels in a sensor. Assuming you ignore the masked pixels, you will usually get one extra row and column at the edges of the RAW image data as compared to the interpolated image. So, if you have a camera with 5184x3456 (i.e. 1D X) pixels, that is the EXACT pixel count as far as exported TIFF or JPEG images go. The actual RAW pixel count, ignoring the masked border pixels, would be 5186x3458, as you need that extra set of rows and columns on the outer edge in order to perform interpolation. The actual true RAW pixel dimensions are greater, around 5212x3466 when you do include the masked border pixels (which are used for sensor black and white point calibration).

Regardless of how you slice it, a "pixel" in bayer is a direct unit of two-dimensional SPATIAL measure. A "pixel" in Foveon, the way Sigma defines it, is a three-dimensional measure of both spatial detail and color depth. If you want to compare Foveon to Bayer, you have to remove that third color depth dimension, otherwise you are comparing apples to oranges. Spatially, Foveon sensors have, historically, been significantly lower resolution than bayer sensors. This is no myth, no trickery, there isn't even any anti-Foveon here. As I've said, I love the Foveon concept, I just think that Foveon in the hands of Sigma is in the wrong hands, and I think the way Sigma markets Foveon is so misleading that it ramps up prospective buyers hopes to levels that simply cannot be met. (Either that, or you get gullible saps who buy so fully into Sigma's misleading concept that they are missing the forest for the trees, and therefor missing out on the kind of raw, unmitigated resolving power you can get with some current bayer sensors...which actually includes both the 5D III and D800, probably also the 6D, and for sure all current medium format sensors on the market without question.)

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Furthermore, the D800 and 645D both have more information to start with. They are resolving details that are not even present in the SD1 image at all, despite it's sharpness

No, they DON'T, that's what the image should have told you. I could resize the Sigma-Picture 4 Times and have more resolution, but not more information.

Your conflating two separate concepts. Resolution is an overloaded word, and some of it's "overloads" are invalid. I try to be very specific when I use words like resolution. When I say resolution in this context, I try to always make it very clear that I am talking about resolving power and spatial resolution. These terms refer to very well understood concepts in the world of imaging, and describe a very specific process where by something with a given area is divided into certain discrete elements...such as a real image projected onto a sensor by a lens being "resolved" by each pixel.

What you are referring to is one of the invalid uses of resolution, which refers to image dimensions. Simply upscaling an image does not give you more resolution...it gives you more pixels, but your resolution has not actually increased. By upscaling, you enlarge everything, including the smallest discernible element of detail, such that those smallest elements are also larger. That is not increasing resolution...it is simply increasing the total number of pixels and enlarging your images dimensionally. I rarely ever use the word "resolution" to refer to changes in image dimensions. I usually use the term "image dimensions", or refer to concepts like upscaling or downsampling, to refer to changes in image dimensions.

The resolution I am talking about is not the "resolution" your are talking about. Upscaling an image does not give you more resolution...it simply gives you more pixels, and changes the ratio of pixels to detail. Luminance detail, I might add...when you upscale a Foveon image, you aren't just blurring chrominance information (as is the case with bayer interpolation)...you are ALSO blurring luminance information (which is NOT the case with bayer interpolation...you keep your full luminance information at each pixel.)

So you are correct about not having more information after upscaling. ;)

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A light sharpening filter can deal with the softness in a few seconds, and then the SD1 is at a real disadvantage.

Please try and proove me wrong, the RAW-Data is available for download @dpreview.com  ;)

By the way, the Size of the photodiodes are of course really important, especially on lowlight, but the technology solves some of the problems. On the paper no one could beat my old 5D with ca. 8.2 Microns, but in reality your 1DX would run circles around it  8)

Your argument is a classic fallacy...to claim that technological improvements will only benefit one type of technology. Technological improvements can indeed help Foveon, but at the same time, MASSIVE strides have been and will continue to be made for bayer type sensors as well. Foveon isn't going to be gaining technological advancements in leaps and bounds and suddenly end up well ahead of bayer...it just isn't going to happen.

In this case, the reason the 1D X would run circles around the 5D does not actually have anything to do with pixel size. The 5DC is actually still an excellent performer. I know a few wedding photographers who LOVE their 5DCs, they still produce wonderful images. Technologically, they have high read noise (actually quite high), so the images from a 5DC cannot be pushed around like those from a 1D X or even a 5D III or 6D. The CDS technology used in the 5DC isn't as good as it is today. The individual color filters in the bayer CFA are stronger in the 5DC, which improves native color fidelity, but reduces total sensor Q.E.

So yes, technology does solve some problems. If the Foveon was in the hands of Canon or Sony, I believe it could rapidly become a major contender in the sensor market. I do not believe it would ever offer as much spatial resolution (i.e. true resolving power) as any bayer...as Foveon improves, so too will bayer sensors, and bayer will always have the lead in terms of spatial resolution, assuming your aim is to keep Foveon noise levels as low as bayer levels. Spatially, Foveon could compete directly with bayer if you simply ignored noise levels, however because the red layer is at the bottom, despite silicon's greater transparency to red, your still losing a lot of light by the time the red photodiode senses anything. A spatially-equivalent Foveon is going to be a very noisy sensor.

I think the only way your going to get a true "full color fidelity per pixel" sensor that is actually better than bayer would be if something like TriCCD came along again. Three separate sensors with single-color color filters on them, which receive light from a special prism where each sensor gets a FULL compliment of light of it's given color. You then have full sensitivity, full spatial resolution, in three (or, as should be possible, more) full colors. You would then simply need to convert each RAW color layer into R,G, and B pixels in an output image, no interpolation required (like Foveon, but without the sensitivity and noise issues.) Such a system would be rather bulky, but I do think it would be ideal for those who want everything to be the absolute best. Foveon is just another compromise....spatial resolution for color fidelity, just like bayer is a compromise: color fidelity for spatial resolution.

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Re: Canon's Medium Format
« Reply #147 on: April 02, 2014, 05:38:58 PM »

jrista

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Re: Canon's Medium Format
« Reply #148 on: April 02, 2014, 05:51:41 PM »
If you convert a bayer sensor's data to monochrome, you effectively have just the full detail luminance.

If you can just expand on that a little Jon. When you say 'you' are you referring to the manufacturers setting it up this way ( like the Leica monochrome), or the user converting the RAW to B&W ?

I mean you as in the "you" who is reading my words. ;)

You can use astrophotography editors to read RAW images directly. If you used something like LR or ACR, if you convert to grayscale that is post-demosaicing, so you really wouldn't gain the same benefit. With something like Iris, you can simply read out a RAW image as monochrome data. You might get slight artifacting this way...silicon really is not very sensitive to blue at all, so depending on the exact camera you are using, the blue pixels might end up a bit darker. I recently purchased a tool called PixInsight, an astrophotography processing tool (exceptionally powerful). PixInsight has something called PixelMath, which allows you to run just about any algorithm you can imagine on your images. If you have a blue darkening problem when converting a RAW image directly to luminance, you could easily apply some pixel math to reweight some luminance information, stealing a little bit from green and adding it to blue. Or you could artificially apply some digital amplification to just the blue pixels, which would make them a little noisier, but normalize the brightness.

Regardless of how you correct any blue deficiencies (which, BTW, would also be present in a Foveon sensor, as silicon is silicon), Bayer sensors generally gather roughly the same average amount of light at every sensor pixel. Absent any color, that is your full resolution DETAIL...and it really doesn't need any interpolation, all it might need is some massaging to normalize luminance levels in post. Blue is just a noisy channel because of lower natural sensitivity levels...we've all been living with that fact ever since we started using digital cameras. Everyone knows about it from the noise in their blue skies or the blue paint on that car or the blue dye in that girls hair.

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Re: Canon's Medium Format
« Reply #149 on: April 02, 2014, 06:28:21 PM »
...or the blue dye in that girls hair.

Does it have to be a girl?   :P


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Re: Canon's Medium Format
« Reply #149 on: April 02, 2014, 06:28:21 PM »