July 25, 2014, 09:21:20 PM

Author Topic: Can Canon deliver a FF sensor that is class leading?  (Read 7993 times)

GMCPhotographics

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #30 on: June 04, 2014, 05:11:40 AM »
Nikon have been splicing between Canon's niches for years. Their D700 for example sat between Canon's prosumer 5DII and 1D series. Canon has invented the various niches to start with (the 300D / 20D and 5D come to mind) and most of the other manufactures have copied and spliced to put cameras whihc appeal between canon's niches. The 1DX and 5DIII are easily Canon's finest cameras to date and certainly the most versatile. But neither of them are sitting in the niches which they were originally envisioned. The 5D has certainly gone up spec and the 1D has become more versatile, full frame and high frame rate.

I think that the MP war is essentially over, anything over 20mp is quite questionable. There has been plenty of articals stating that the detail difference between a good 5DIII frame and a good D800 frame is marginal. Sure there are differences, but it's not 30% better. So it's reasonable to assume there is a law of diminishing returns with sensor density.

Yes Nikon currently have more recoverability in their raw shadows, but there is more to a camera than that one feature. In a simular way, there is more to a camera than MP.

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #30 on: June 04, 2014, 05:11:40 AM »

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #31 on: June 04, 2014, 05:52:10 AM »
Yes Nikon currently have more recoverability in their raw shadows, but there is more to a camera than that one feature. In a simular way, there is more to a camera than MP.

+1

would love to see a new 7Dii with the same MP, but an improved AF (like 5Diii), a higher speed and less noise. The main reason I don't use my 7D that much anymore is that my 5Diii is doing so much better of AF, even for sports I take the 5Diii. So I fully agree, it's not the high MP that makes a body exceptional, but the combination of all the included features. I see a lot of remarks here about more MP, but the flagship 1-DX is only 18mp, and isn't the 1-DX a top product in the market? also the D4s has no 20mp, why? There is more to a camera than MP.


This is just the same discussion as the processors of the PC. Many years ago we started with 4.77Mhz, 200Mhz, 1Ghz, 2Ghz, 3Ghz. Now look around, market did find out that faster had more troubles for instance the heat coming from these device. That's why they started developing 2-core, 4-core, 6-core, 8-core processors but mainly running on speeds closer to 2 Ghz then 3 Ghz.

Canon is looking for the same, they didn't increase the MP of the 70D that much, but introduced the dual pixel technology. Isn't that comparable to the 2-core? In the beginning everyone was skeptical, it was no 3 Ghz anymore, but only 2-core. No one talks about processor speeds anymore. So in a few years we might all say: Wooow, Canon is really leading, they introduced first the dual pixel technology.

So please for me, no higher MP but rather further improvements on noise, AF, ...

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #32 on: June 04, 2014, 07:28:57 AM »
So, while I understand what your trying to say...I think it's a misnomer. Dynamic range is itself defining what's usable...so saying that you can only use part of what's usable... Redundant and inaccurate. And, incorrect. ;P

Ok, thanks for explaining, I'm really not much of a tech geek even after all this time on CR :-p ... so for my education and to avoid further confusion: With which word(s) would you label the dynamic range starting from the shadows when no banding is visible anymore? Because that's what I called "usable" as fpn is what makes your shot "unusable".

That is dynamic range. The definition, in mathematical terms, is 20 * log(MaxSignal/NoiseRMS), to get dynamic range in decibels. The NoiseRMS is the Root Mean Square of the noise...basically if you sampled the actual noise in each pixel, and computed the RMS from that, that would be your noise floor. Dynamic range describes the usable potential signal range from the noise floor to the maximum signal (saturation point, in the case of ISO, that is also the Full Well Capacity, FWC.)

Maximum signal strength defines the range from "zero to"...if you had no noise, you would have the full range, say from 0.000...1e- to 76606e- (in the case of the 6D). If you could use the full potential signal range, the formula above becomes 20 * log(MaxSignal/0)...but you can't do that, it's divide by zero, which is undefined (undefined because the value becomes infinite...but infinity is also technically undefined). So, if you had no noise, you would have infinite dynamic range. Because noise exists, dynamic range must therefor be something less than infinity. You can keep lowering the noise floor. In astrophotography, we use supercooled CCD cameras that have extremely low dark current (while a DSLR may have as much as 20e-/s/px, a cooled CCD can have as little as 0.002e-/s/px), extremely high Q.E. (77% with Sony's new ICX CCDs is not uncommon, and some of the older Kodak KAF sensors (now owned by TrueSenseImaging, TSI) had as much as 90% Q.E.), and very low read noise at optimal gain. Further, we use more extreme noise reduction techniques, such as bias and dark calibration, which eliminates fixed sensor pattern noise as well as hot pixel noise, leaving us with what is effectively a pure gaussian read noise and photon shot noise signal. We then average together dozens of individual light frames to reduce noise even more (reduction is SQRT(subCount), so if we stack 100 subs, we get 1/10th the noise). In astrophotography, dynamic range of a final integration can be 25-30 stops or more (and we do "stretching", basically shadow lifting, that is so extreme it would make the D800 cry at how utterly sucky it is! :P). But it's still not infinite DR, because there is still noise. There is always noise. :P
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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #33 on: June 04, 2014, 08:17:54 AM »
There is always noise.

Yeah, but there will be a lot less of it once we have fuel cell-powered Peltier cooled sensors….  :D
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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #34 on: June 04, 2014, 08:30:00 AM »
...
Who says?  FWIW I don't believe that the flat spot has anything to do with the sensor at all -- it is due to the noise being dominated by that of the ADC which follows the sensor in the Canon designs.  If you really dig into things you will find that the Canon sensors are actually the class leaders in terms of dynamic range, they just foul it up in terms of their system architecture.  The answer to the question "can Canon deliver a class leading sensor" is yes... they already do.  Take a look at the data from Sensorgen for the 5DIII for example:  Min read noise 2.4e-, FWC=67531 for a DR of 14.7 stops.

And Nikon's D4 would whip everything from Canon quite nicely then.

Quote
If they were to put an ADC on-chip similar to what Sony does, they would have equivalent performance maybe even better.

What Canon needs is a "class leading" system architecture and ADC.  This is a nit, I know but it is important because Canon DOES have class leading sensors and has had them for quite some time.

If you mean "system architecture" to mean "sensor architecture", then yes because the ADC is an integral part of the sensor.

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #35 on: June 04, 2014, 08:31:27 AM »
I think we should step back and put things into perspective with camera bodies in general.

Do we forget that these things go out of date really quickly? I mean in the view of a decade, we used to think the 1D was the pinnacle of sensor design and now it serves as a door stop. But you know what we've kept since possibly that 1D? Our lenses.

Sure the 5D3 is behind in MP and DR but who cares? We have Uber sharp lenses like the 24-70II and 70-200II... etc... eventually the 5D3 and the d800 will be doorstops but we might still have those lenses. 

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #36 on: June 04, 2014, 10:09:00 AM »
I think we should step back and put things into perspective with camera bodies in general.

Do we forget that these things go out of date really quickly? I mean in the view of a decade, we used to think the 1D was the pinnacle of sensor design and now it serves as a door stop. But you know what we've kept since possibly that 1D? Our lenses.

Sure the 5D3 is behind in MP and DR but who cares? We have Uber sharp lenses like the 24-70II and 70-200II... etc... eventually the 5D3 and the d800 will be doorstops but we might still have those lenses.

I've been arguing this point for about 2 years now.  The DxO mark followers love to include noise and moire as part of their "detail" and "resolution."
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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #36 on: June 04, 2014, 10:09:00 AM »

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #37 on: June 04, 2014, 10:53:41 AM »
...
Who says?  FWIW I don't believe that the flat spot has anything to do with the sensor at all -- it is due to the noise being dominated by that of the ADC which follows the sensor in the Canon designs.  If you really dig into things you will find that the Canon sensors are actually the class leaders in terms of dynamic range, they just foul it up in terms of their system architecture.  The answer to the question "can Canon deliver a class leading sensor" is yes... they already do.  Take a look at the data from Sensorgen for the 5DIII for example:  Min read noise 2.4e-, FWC=67531 for a DR of 14.7 stops.

And Nikon's D4 would whip everything from Canon quite nicely then.

Quote
If they were to put an ADC on-chip similar to what Sony does, they would have equivalent performance maybe even better.

What Canon needs is a "class leading" system architecture and ADC.  This is a nit, I know but it is important because Canon DOES have class leading sensors and has had them for quite some time.

If you mean "system architecture" to mean "sensor architecture", then yes because the ADC is an integral part of the sensor.
When I say system architecture, I mean exactly that -- how the system is architected.  In Sony's case they have optimized the architecture to minimize pattern noise and overall system read noise -- it is an excellent design in that respect.  They achieved this through the use of a distributed ADC structure that they were able to implement on-chip.  It is a clever and innovative approach (originally invented by IBM, BTW).   

Canon has chosen to design their system in am more traditional way using an ADC off-chip.  This has consequences, since it requires a higher speed, more complex pipelined ADC which will not yield the same effective number of bits (ENOB) of the Sony approach.

This is a classic study in system architecture where you can design two radio receivers using the same high performance front end LNA (low noise amplifier) but without optimizing your noise lineup for DR one doesn't work as well as the other.  In this case it isn't a satellite receiver but a camera but the principles are the same.

FWIW, the ADC that canon is using is state of the art, they have a 14 bit converter that is probably getting about 12.5 ENOB at 40 MSPS.  That is about as good as it gets for a pipelined ADC running that fast.  Both companies have state of the art sensors which appear to yield pretty much the same performance, Sony has done a better job on system design by optimizing the system noise line up for this one particular parameter.

If you are going to talk about sensors you need to talk about sensors, the sensor is only one part of the overall system and it is this overall system implementation that determines the noise figure and dynamic range of the camera.  In the case of Canon the sensor and ADC are separate chips.
« Last Edit: June 04, 2014, 11:13:01 AM by David Hull »

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #38 on: June 04, 2014, 11:19:50 AM »
I'd be capturing more high-res blur...

LOL...I love that description.

This has been an interesting and informative thread, especially learning about on- and off-sensor ADC and the effect that choice has on noise, et cetera. Thanks for all the super-geek explanations. Much of it goes over my head, but I'm starting to get the idea.

In the meantime, I sure love taking photos. :P

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #39 on: June 04, 2014, 03:22:01 PM »
...
Who says?  FWIW I don't believe that the flat spot has anything to do with the sensor at all -- it is due to the noise being dominated by that of the ADC which follows the sensor in the Canon designs.  If you really dig into things you will find that the Canon sensors are actually the class leaders in terms of dynamic range, they just foul it up in terms of their system architecture.  The answer to the question "can Canon deliver a class leading sensor" is yes... they already do.  Take a look at the data from Sensorgen for the 5DIII for example:  Min read noise 2.4e-, FWC=67531 for a DR of 14.7 stops.

And Nikon's D4 would whip everything from Canon quite nicely then.

Only at lower ISO, and only marginally. In every other respect, the Canon 1D X trounces the D4. In the most important aspects, frame rate and AF system (arguably the critical traits of such cameras), the 1D X has the technological and performance lead.

Quote
If they were to put an ADC on-chip similar to what Sony does, they would have equivalent performance maybe even better.

What Canon needs is a "class leading" system architecture and ADC.  This is a nit, I know but it is important because Canon DOES have class leading sensors and has had them for quite some time.

If you mean "system architecture" to mean "sensor architecture", then yes because the ADC is an integral part of the sensor.

Completely incorrect. In Canon "systems", the ADC is OFF-DIE. I don't know how many times I've written that when answering you...but that means it is NOT an integral part of the sensor. Canon's ADC units are in their off-sensor die digital signal processors...the DIGIC chips. That, as it turns out, is actually how MOST CMOS image sensors are designed. Sony Exmor is currently somewhat unique in that it has a column-parallel ADC integrated right into the sensor. Canon has patents for that kind of technology...they just haven't employed it in a commercial product yet.

So for the time being, David is correct...it's "system architecture", not "sensor architecture".
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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #40 on: June 04, 2014, 03:22:37 PM »
There is always noise.

Yeah, but there will be a lot less of it once we have fuel cell-powered Peltier cooled sensors….  :D

Indeed! :D I'm just counting the days...can't be that far off... ;)
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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #41 on: June 04, 2014, 03:26:47 PM »
...
Who says?  FWIW I don't believe that the flat spot has anything to do with the sensor at all -- it is due to the noise being dominated by that of the ADC which follows the sensor in the Canon designs.  If you really dig into things you will find that the Canon sensors are actually the class leaders in terms of dynamic range, they just foul it up in terms of their system architecture.  The answer to the question "can Canon deliver a class leading sensor" is yes... they already do.  Take a look at the data from Sensorgen for the 5DIII for example:  Min read noise 2.4e-, FWC=67531 for a DR of 14.7 stops.

And Nikon's D4 would whip everything from Canon quite nicely then.

Quote
If they were to put an ADC on-chip similar to what Sony does, they would have equivalent performance maybe even better.

What Canon needs is a "class leading" system architecture and ADC.  This is a nit, I know but it is important because Canon DOES have class leading sensors and has had them for quite some time.

If you mean "system architecture" to mean "sensor architecture", then yes because the ADC is an integral part of the sensor.
When I say system architecture, I mean exactly that -- how the system is architected.  In Sony's case they have optimized the architecture to minimize pattern noise and overall system read noise -- it is an excellent design in that respect.  They achieved this through the use of a distributed ADC structure that they were able to implement on-chip.  It is a clever and innovative approach (originally invented by IBM, BTW).   

Canon has chosen to design their system in am more traditional way using an ADC off-chip.  This has consequences, since it requires a higher speed, more complex pipelined ADC which will not yield the same effective number of bits (ENOB) of the Sony approach.

This is a classic study in system architecture where you can design two radio receivers using the same high performance front end LNA (low noise amplifier) but without optimizing your noise lineup for DR one doesn't work as well as the other.  In this case it isn't a satellite receiver but a camera but the principles are the same.

FWIW, the ADC that canon is using is state of the art, they have a 14 bit converter that is probably getting about 12.5 ENOB at 40 MSPS.  That is about as good as it gets for a pipelined ADC running that fast.  Both companies have state of the art sensors which appear to yield pretty much the same performance, Sony has done a better job on system design by optimizing the system noise line up for this one particular parameter.

If you are going to talk about sensors you need to talk about sensors, the sensor is only one part of the overall system and it is this overall system implementation that determines the noise figure and dynamic range of the camera.  In the case of Canon the sensor and ADC are separate chips.

Aah! That's a breath of fresh air! Thanks for the post! :D
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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #42 on: June 04, 2014, 03:59:24 PM »
...
Who says?  FWIW I don't believe that the flat spot has anything to do with the sensor at all -- it is due to the noise being dominated by that of the ADC which follows the sensor in the Canon designs.  If you really dig into things you will find that the Canon sensors are actually the class leaders in terms of dynamic range, they just foul it up in terms of their system architecture.  The answer to the question "can Canon deliver a class leading sensor" is yes... they already do.  Take a look at the data from Sensorgen for the 5DIII for example:  Min read noise 2.4e-, FWC=67531 for a DR of 14.7 stops.

And Nikon's D4 would whip everything from Canon quite nicely then.

Quote
If they were to put an ADC on-chip similar to what Sony does, they would have equivalent performance maybe even better.

What Canon needs is a "class leading" system architecture and ADC.  This is a nit, I know but it is important because Canon DOES have class leading sensors and has had them for quite some time.

If you mean "system architecture" to mean "sensor architecture", then yes because the ADC is an integral part of the sensor.
When I say system architecture, I mean exactly that -- how the system is architected.  In Sony's case they have optimized the architecture to minimize pattern noise and overall system read noise -- it is an excellent design in that respect.  They achieved this through the use of a distributed ADC structure that they were able to implement on-chip.  It is a clever and innovative approach (originally invented by IBM, BTW).   

Canon has chosen to design their system in am more traditional way using an ADC off-chip.  This has consequences, since it requires a higher speed, more complex pipelined ADC which will not yield the same effective number of bits (ENOB) of the Sony approach.

This is a classic study in system architecture where you can design two radio receivers using the same high performance front end LNA (low noise amplifier) but without optimizing your noise lineup for DR one doesn't work as well as the other.  In this case it isn't a satellite receiver but a camera but the principles are the same.

FWIW, the ADC that canon is using is state of the art, they have a 14 bit converter that is probably getting about 12.5 ENOB at 40 MSPS.  That is about as good as it gets for a pipelined ADC running that fast.  Both companies have state of the art sensors which appear to yield pretty much the same performance, Sony has done a better job on system design by optimizing the system noise line up for this one particular parameter.

If you are going to talk about sensors you need to talk about sensors, the sensor is only one part of the overall system and it is this overall system implementation that determines the noise figure and dynamic range of the camera.  In the case of Canon the sensor and ADC are separate chips.

Aah! That's a breath of fresh air! Thanks for the post! :D
Yea... I think that DxO does the photographic world a great disservice by claiming to test sensors when they actually test the entire chain.  Lots of folks get very confused.  I don't know why they don't take it to the finish line and do what Bob did at Sensorgen and bring it back to the actual sensor performance.  Maybe they don't feel good about posting a result based on an indirect measurement.

Incidentally if the ADC is actually on-board the DiGiC, that would explain a lot since they probably pick up a lot of analog noise bringing the analog signals from the sensor assembly down to the mainboard.  I thought that they had an actual ADC chip right on the back of the sensor subassembly.  Seems to me I have seen it that way in some of the teardowns.

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #42 on: June 04, 2014, 03:59:24 PM »

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #43 on: June 04, 2014, 04:10:04 PM »
I think that DxO does the photographic world a great disservice by claiming to test sensors when they actually test the entire chain.  Lots of folks get very confused.

The disservice done by DxO is in the reduction of their measurements to Scores which are biased and determined in an undisclosed manner. 

What good would it do to test the sensor and ADC separately?  If the sensor is good and the ADC is poor, it's not as if I can just pop a better ADC into my camera.  Testing anything but the 'entire chain' would have no real-world utility (except fueling speculation about what might or might not be possible at some unspecified future time).
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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #44 on: June 04, 2014, 06:52:34 PM »
Quote from: neuroanatomist link=topic=20935.msg401699#msg401699
?..Testing anything but the 'entire chain' would have no real-world utility (except fueling speculation about what might or might not be possible at some unspecified future time).
I agree. Testing without pushing to the limits is no testing. By definition the CMOS includes the ADC. No matter on or off die. And usually there are more than one on the chain serial-wise. Additionally the dark current is important too.

Have you ever tried to shoot video with the 550d? AFAIK its CMOS gets heated, which makes me believe that there still must be some kind of  ADC to each pixel.

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Re: Can Canon deliver a FF sensor that is class leading?
« Reply #44 on: June 04, 2014, 06:52:34 PM »