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Author Topic: CCD vs CMOS - What is the current state?  (Read 8863 times)

SZRitter

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CCD vs CMOS - What is the current state?
« on: April 14, 2014, 10:41:03 am »

So, after much Googling, it seems I am as confused as before. I've been revisiting old images that were shot on a Nikon D200, and the colors/feel of it seems so much better than the D7000 and E-M5 images.

1) Outside of Medium Format/Leica, is there any interchangeable lens cameras still being made with CCD?
2) My understanding  is that the technical superiority of CMOS is in it's ability to read and possibly noise reduction, especially at higher ISO, did I miss something there?
3) With the demands of video on the chip, it seems CMOS is the only one to handle that properly. This means that CCD would also be unsuitable for mirrorless designs. Am I correct?
4) If read time was not important (i.e. not needing more than 1 frame per second), dedicated to stills, and ISO is usually between 100 and 800, typically at the 100, wouldn't CCD make more sense?
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BJL

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Re: CCD vs CMOS - What is the current state?
« Reply #1 on: April 14, 2014, 11:45:41 am »

So, after much Googling, it seems I am as confused as before. I've been revisiting old images that were shot on a Nikon D200, and the colors/feel of it seems so much better than the D7000 and E-M5 images.
This has been much debated, but I am fairly sure that you are seeing differences due to other factors, like the different color filter array designs and different JPEG processing approaches in different cameras.  The difference between CCD and CMOS technology only starts after the light has gone through the color filters and has been detected by converting the light signal to electron counts, so it is very hard to see how the subsequent electronic processing could affects the colors in the results.

1) Outside of Medium Format/Leica, is there any interchangeable lens cameras still being made with CCD?
AFAIK, no.

2) My understanding  is that the technical superiority of CMOS is in it's ability to read and possibly noise reduction, especially at higher ISO, did I miss something there?
Modern active pixel CMOS sensors have less sensor noise (not so much "noise reduction" as "noise avoidance"), which increases the dynamic range and shadow quality at any ISO speed, not just at high speeds.

3) With the demands of video on the chip, it seems CMOS is the only one to handle that properly. This means that CCD would also be unsuitable for mirrorless designs. Am I correct?
Yes, the full frame type of CCD used in all MF cameras until recently cannot do real time live view or video, so they are useless also in SLRs with a live view option. Interline CCDs (as used in some video cameras and some older and/or cheaper compact digital cameras) can do live view, but their still image IQ is inferior, so no SLR uses them anymore.

4) If read time was not important (i.e. not needing more than 1 frame per second), dedicated to stills, and ISO is usually between 100 and 800, typically at the 100, wouldn't CCD make more sense?
Once the very dubious idea that CMOS has inherently inferior colors is ruled out, I see no remaining advantage for CCD at any ISO speed: the advantage of lower noise and great dynamic range is there at any ISO speed, even if less important at low speeds, and the potential advantage of live view is always there.  At most, the advantages of CMOS are diminished or even become negligible in some uses, but are not turned to a disadvantage.
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SZRitter

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Re: CCD vs CMOS - What is the current state?
« Reply #2 on: April 14, 2014, 12:00:08 pm »

Once the very dubious idea that CMOS has inherently inferior colors is ruled out, I see no remaining advantage for CCD at any ISO speed: the advantage of lower noise and great dynamic range is there at any ISO speed, even if less important at low speeds, and the potential advantage of live view is always there.  At most, the advantages of CMOS are diminished or even become negligible in some uses, but are not turned to a disadvantage.

All my images are from RAW files, not JPEG, so you can rule that out. I have been revisiting the D200 files in LR5, and it just seems that the sensor picks up colors differently. But as you point out, that could be as much the color array/filter stack as it is the sensor itself. All I know is, for some shots (lets say in studio), I almost wish I had a sensor that performed like my D200, just larger (i.e. Full Frame or MF) and with above 20MP.

I think the easiest way for me to put it, and it may not be quite right, but I lack the exact words, is that the D200 images seem to have a smoother tonal response than the D7000.
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BJL

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CFAs, and the trade-off between low-light ability and color accuracy
« Reply #3 on: April 14, 2014, 01:33:44 pm »

All my images are from RAW files, not JPEG, so you can rule that out. ... as you point out, that could be as much the color array/filter stack as it is the sensor itself.
CFA differences is my best guess, and there might even be a bad trend in DSLRs (as opposed to MF, at least so far) toward favoring ever-improving low-light performance and low noise over color accuracy, which can push CFA designs toward ones that let through a wider range of wavelengths ("red" letting in a bit more of the orange and yellow, etc.) which counts more photons and so improves SNR, but at the cost of less accurate color handling. That is at least a risk when camera evaluations are so driven by lab measurements of SNR and scrutinizing test shots at high ISO speeds, while color accuracy measurements are less emphasized.

On this subject, the smaller sensors of compact cameras often have higher quantum efficiency (a higher fraction of all incoming light gets through the microlenses and CFA to the sensor) than larger DSLR sensors, even when from the same company (i.e. Sony!). Given that the larger, more expensive sensors should have a natural advantage in QE, this has to be a deliberate decision to push the trade-off between lower noise vs better color accuracy more toward the low noise side with the smaller sensors.
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ErikKaffehr

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Hi,

Regarding CFA designs, DxO mark actually measures something called SMI, Sensor Metamerism Index, that is a measure of how well a sensor can reproduce colour. Some observers have found it highly relevant to colour reproduction ability (Tim Parkin) but some others (Iliah Borg) say it is irrelevant.

I don't necessary think that very narrow filters are optimal.

The articles below may be of some interest

http://dougkerr.net/Pumpkin/articles/Metameric_Error.pdf
http://dougkerr.net/Pumpkin/articles/Sensor_Colorimetry.pdf

Best regards
Erik


CFA differences is my best guess, and there might even be a bad trend in DSLRs (as opposed to MF, at least so far) toward favoring ever-improving low-light performance and low noise over color accuracy, which can push CFA designs toward ones that let through a wider range of wavelengths ("red" letting in a bit more of the orange and yellow, etc.) which counts more photons and so improves SNR, but at the cost of less accurate color handling. That is at least a risk when camera evaluations are so driven by lab measurements of SNR and scrutinizing test shots at high ISO speeds, while color accuracy measurements are less emphasized.

On this subject, the smaller sensors of compact cameras often have higher quantum efficiency (a higher fraction of all incoming light gets through the microlenses and CFA to the sensor) than larger DSLR sensors, even when from the same company (i.e. Sony!). Given that the larger, more expensive sensors should have a natural advantage in QE, this has to be a deliberate decision to push the trade-off between lower noise vs better color accuracy more toward the low noise side with the smaller sensors.
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BJL

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Regarding CFA designs, DxO mark actually measures something called SMI, Sensor Metamerism Index, that is a measure of how well a sensor can reproduce colour.
Indeed: but DxO is not a major market driver (outside of geeky forums) and overall, the emphasis in website testing and reviews and blog discussions is far more on high ISO noise and DR than it is on colour accuracy or "colors that hold up well under post-processing", so I suspect that favorable noise measurements and noise-free high ISO sample shots have far more benefit for sales, motivating the marketing department to encourage the engineering department to set the design priorities accordingly.
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BernardLanguillier

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Re: CCD vs CMOS - What is the current state?
« Reply #6 on: May 11, 2014, 09:13:22 am »

This is a very good reason why, on top of more or less talented all rounders like the D800/5DIII, I believe that a D4x dedicated to low ISO shooting could still make sense.

Cheers,
Bernard

ErikKaffehr

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Re: CCD vs CMOS - What is the current state?
« Reply #7 on: May 11, 2014, 04:45:56 pm »

Hi,

Looking at DxO data I don't feel that much of a compromise is made for high ISO.

There is a rumour of a new 54 MP (or so Sony sensor) with new capabilities, may be worth waiting for. It may to take some time to go into production, as it is very expensive to make.

Best regards
Erik


This is a very good reason why, on top of more or less talented all rounders like the D800/5DIII, I believe that a D4x dedicated to low ISO shooting could still make sense.

Cheers,
Bernard

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SZRitter

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Re: CCD vs CMOS - What is the current state?
« Reply #8 on: May 12, 2014, 10:19:05 am »

This is a very good reason why, on top of more or less talented all rounders like the D800/5DIII, I believe that a D4x dedicated to low ISO shooting could still make sense.

Cheers,
Bernard


Being a m43 guy, I keep hoping for this. One camera with sensor tuned to lower ISO for studio and landscape, then another tuned for versatility for street, sports and events.
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BJL

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This is a very good reason why, on top of more or less talented all rounders like the D800/5DIII, I believe that a D4x dedicated to low ISO shooting could still make sense.
On one hand hand, I too can see a niche for a body from Nikon (and likewise one from Canon) that combines a high resolution sensor like that of the D800 with a more robust, top-of-the-line body in the spirit of the F6 --- including omitting the integrated vertical grip as the F6 did, because that seems more relevant to the fast-paced work for which the D4s in intended, and an accessory vertical grip seems a more flexible approach.

But on the other hand, this niche seems rather small now that the D800 is around, and the fact that both Canon nor Nikon have in recent years only offered their best, most bullet-proof high-end bodies in combination with high frame rate, high ISO, moderate resolution sensors makes me suspect that developing a camera of this "D4x" or "1Ds" type is no longer considered to be sufficiently profitable.

« Last Edit: May 13, 2014, 03:20:58 pm by BJL »
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DeanChriss

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Re: CCD vs CMOS - What is the current state?
« Reply #10 on: May 13, 2014, 11:57:06 am »

IMHO data throughput is always the problem. I'd like high resolution and low noise for landscapes AND wildlife, but there has never been a high resolution low noise camera with both a high enough frame rate and adequate servo AF for things like birds in flight. There has always been a big gap between what I'll call landscape cameras and action cameras, with the compromise revolving around data throughput. An "in between" camera with something like 24MP at 9 FPS has been possible for a while. That's the same throughput as a Canon 1DX, with a lower frame rate and higher resolution. I'd buy it in a heartbeat as a real jack of all trades camera, but I think many would see it as a "neither here nor there" sort of camera and it might not be very popular. Unless that changes one must either have two different cameras or struggle in one realm with a camera meant for the other.
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Paul2660

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Re: CCD vs CMOS - What is the current state?
« Reply #11 on: May 13, 2014, 04:17:31 pm »

The new Sony A77ii fits that role perfectly. 24mp 12fps. Still APS-C but for firds or most wildlife I prefer the 1.5 crop.

Nikon will soon follow I am sure and Canon maybe the long awaited 7Dmkii?

Paul
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BernardLanguillier

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Re: CCD vs CMOS - What is the current state?
« Reply #12 on: May 13, 2014, 08:36:07 pm »

For what it is worth, the Nikon V3 does 20 fps with an AF that is nothing short of stellar.

Image quality is pretty good in good light too, certainly not much worse than that of the DSLRs we used to use a few years ago with excellent results.

http://www.dxomark.com/Cameras/Compare/Side-by-side/Nikon-1-V3-versus-Canon-EOS-1D-Mark-III-versus-Nikon-D2X___947_434_207

With a lens such as the Nikon 70-200 f4 VR, you get an excellent 540mm f4 equivalent in a compact and very light package that is super easy to handhold.

Cheers,
Bernard

ErikKaffehr

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Re: CCD vs CMOS - What is the current state?
« Reply #13 on: May 14, 2014, 12:07:59 am »

Hi Bernard,

Do you get that 20 fps with stellar AF on 70-200 f4 VR?

What about image quality? For sure the Nikon zoom is probably great, but does it resolve high enough for those tiny pixels?

Best regards
Erik

For what it is worth, the Nikon V3 does 20 fps with an AF that is nothing short of stellar.

Image quality is pretty good in good light too, certainly not much worse than that of the DSLRs we used to use a few years ago with excellent results.

http://www.dxomark.com/Cameras/Compare/Side-by-side/Nikon-1-V3-versus-Canon-EOS-1D-Mark-III-versus-Nikon-D2X___947_434_207

With a lens such as the Nikon 70-200 f4 VR, you get an excellent 540mm f4 equivalent in a compact and very light package that is super easy to handhold.

Cheers,
Bernard

« Last Edit: May 14, 2014, 01:05:56 am by ErikKaffehr »
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