*UPDATE* EOS 70D is Coming, The Future of Pro APS-C Will Change

[eyeland]

As much as I hate to divert attention away from the above posts (which filled in some serious gaps in my knowledge) I thought I'd mention that, over at the dark side, based on the addition of a Nikon DSLR SKU and an upcoming press conference, the admin speculates that the D7000 replacement will be announced in the coming week.
If that is true, I guess it will "compel" Canon to react?

 

[jrista]

As much as I hate to divert attention away from the above posts (which filled in some serious gaps in my knowledge) I thought I'd mention that, over at the dark side, based on the addition of a Nikon DSLR SKU and an upcoming press conference, the admin speculates that the D7000 replacement will be announced in the coming week.
If that is true, I guess it will "compel" Canon to react?

If Canon does "react", my guess is it would only be on paper. I think Canon will hold out as long as they need to in order to produce a quality product.

 

[RMC33]

As much as I hate to divert attention away from the above posts (which filled in some serious gaps in my knowledge) I thought I'd mention that, over at the dark side, based on the addition of a Nikon DSLR SKU and an upcoming press conference, the admin speculates that the D7000 replacement will be announced in the coming week.
If that is true, I guess it will "compel" Canon to react?

If Canon does "react", my guess is it would only be on paper. I think Canon will hold out as long as they need to in order to produce a quality product.

I would hope so.

 

[dlleno]

As much as I hate to divert attention away from the above posts (which filled in some serious gaps in my knowledge) I thought I'd mention that, over at the dark side, based on the addition of a Nikon DSLR SKU and an upcoming press conference, the admin speculates that the D7000 replacement will be announced in the coming week.
If that is true, I guess it will "compel" Canon to react?

If Canon does "react", my guess is it would only be on paper. I think Canon will hold out as long as they need to in order to produce a quality product.

+1, with the important distinction that "as long as they need to" is not the same as "as long as possible". We may be seeing, as you imply over on the big megapixel thread, the results of a company that invests conservatively. that is, perhaps economics drove them not to invest heavily and take risks in maturing their 180nm process. Accordingly, their decisions are the best to keep the company healthy, not to win every last spec war. ergo, a 5D mark iii that soundly met customers needs with essentially incremental improvements to legacy sensor technology.

without the converse being somewhat evident over on the Nikon side (with news of plummeting stock prices, influenced by their debt structure) I wouldn't have otherwise suggested this, but it appears that the D800 may have been a very risky investment, perhaps for both Sony and Nikon. The decision certainly made some waves, but I'm not so sure that Canon is trembling in their boots; their conservative nature just compels a more measured approach to economics and corporate health.

 

[jrista]

As much as I hate to divert attention away from the above posts (which filled in some serious gaps in my knowledge) I thought I'd mention that, over at the dark side, based on the addition of a Nikon DSLR SKU and an upcoming press conference, the admin speculates that the D7000 replacement will be announced in the coming week.
If that is true, I guess it will "compel" Canon to react?

If Canon does "react", my guess is it would only be on paper. I think Canon will hold out as long as they need to in order to produce a quality product.

+1, with the important distinction that "as long as they need to" is not the same as "as long as possible". We may be seeing, as you imply over on the big megapixel thread, the results of a company that invests conservatively. that is, perhaps economics drove them not to invest heavily and take risks in maturing their 180nm process. Accordingly, their decisions are the best to keep the company healthy, not to win every last spec war. ergo, a 5D mark iii that soundly met customers needs with essentially incremental improvements to legacy sensor technology.

without the converse being somewhat evident over on the Nikon side (with news of plummeting stock prices, influenced by their debt structure) I wouldn't have otherwise suggested this, but it appears that the D800 may have been a very risky investment, perhaps for both Sony and Nikon. The decision certainly made some waves, but I'm not so sure that Canon is trembling in their boots; their conservative nature just compels a more measured approach to economics and corporate health.

My thoughts exactly. +1

 

[CarlTN]

Jrista, excellent points. I should have known "color filter array", it's just that your post was so long, my brain had reduced its frames per second.

I didn't necessarily mean that pro cameras would need to eliminate the pentaprism to reduce weight...I was speaking generally about each of those aspects of cameras, that many people think will go away someday. However, the larger body required to encompass the pentaprism, does indeed add weight. Not that I dislike pentaprisms, I do. As for the batteries...well in a pro camera they are three 18650 rechargable lithium ion...and each one to my hand, feels not much heavier than a AA (I recently bought several to use in some bright LED flashlights, and these are 3000 mah). Each are 3.7 volts...

If Panasonic color splitting technique is so superior, why haven't the other companies developed their own versions? Isn't this technique too new to really predict it will be the future of sensor design?

Hjulennison, I disagree on the in-effectiveness of the Foveon sensor. I used to own one...and if I worked within its limitations, it provided a very wide, very saturated color palette, that was enjoyable to further manipulate in PS. I also disagree that pixel photosite size/area is not a factor, because it just is. The bigger the area, the more photons fall on that area.

 

[jrista]

If Panasonic color splitting technique is so superior, why haven't the other companies developed their own versions? Isn't this technique too new to really predict it will be the future of sensor design?

It is superior in that it does not absorb or reflect light...it splits it, and one way or another, ALL of the light reaches a photodiode somewhere. Filtration is kind of a double-edged sword. Electronic noise increases with heat (which is why supercooling electronics to -80°C nearly eliminates electronic noise), and filtration generally causes photons to be absorbed into the molecules of the filter...that increases the kinetic vibration of the atoms of those molecules, which is what heat is. So, not only are you literally losing light (which reduces Q.E.), which causes more noise because of a lesser signal strength...you are also increasing heat, which exacerbates the dark current noise present in the circuit.

If, instead of absorbing the energy of light and converting it into heat, we simply split that light and redirected it to the appropriate pixels...we would increase the signal strength and eliminate heat, doubling the benefit.

As for whether this technology will replace CFA's, I cannot say. Some people would say there are thousands of ways of doing the same thing. There may be a thousand ways of building image sensors, but as for each specific concept that is a part of the fabrication of image sensors, I think there are fewer ways. Depending on whether or not a company like Canon can develop their own patents for color splitting that do not infringe upon Panasonic's patents for the same thing, and depending on what kind of judgments are made about the validity of such patents, can affect how broadly the technology is applied in the short term. Patents are explicitly designed to benefit the inventor, allowing them to recoup the costs invested in researching and developing new technologies, and possibly make some profit from the intellectual property, before they become broadly available to competitors.

 

[CarlTN]

Jrista, again, excellent points, a wealth of information! Much obliged. I feel like I'm deep underground, in James Bond's Q Branch camera development facility. Or perhaps inside a giant supertele lens that doubles as the hadron collider...too far? Ok, ok...

The way you're describing it, it sounds like there is no downside. And also, is it even possible that Canon would attempt to pursue the technique now anyway? Their reputation with sensor innovation, is kind of like the speed with which a cure for bubonic plague was found, for the people afflicted back in 500 A.D. Time wasn't on their side! Or it's kind of like, painting a piece of glass with asphalt and some phosphorous...sticking it down inside an old gutted out 1D Mark2, and hoping for the best...

 

[that1guyy]

So, back on topic here...

Where is the 70D? I remember reading a rumor that it will come before March. March is almost here and stlil no concrete sign. The Nikon D7000 is supposed to come out next week. I hope the 70D is able to complete with a new sensor.

 

[CarlTN]

So, back on topic here...

Where is the 70D? I remember reading a rumor that it will come before March. March is almost here and stlil no concrete sign. The Nikon D7000 is supposed to come out next week. I hope the 70D is able to complete with a new sensor.

+ won

We actually were on topic, discussing the sensor.

 

[jrista]

So, back on topic here...

Where is the 70D? I remember reading a rumor that it will come before March. March is almost here and stlil no concrete sign. The Nikon D7000 is supposed to come out next week. I hope the 70D is able to complete with a new sensor.

Well, sensor was kind of the discussion at hand. If I was to predict, with the best of my knowledge, what Canon will come out with in a new APS-C sensor (which, BTW, may not find its way into the 70D...it seems like the 7D would be the better target for new sensor tech), here is what I think:

- 180nm fabrication process
- Copper interlink
- Lightpipe technology
- Per-column amplifiers and column-wise readout
- Power-dieconnect readout logic, which should nearly eliminate noise from dark current (there is a patent for this)
- Higher Q.E., maybe 55% or so (Better IQ, less noise despite an increase in pixel density...not as good as 5D III)
- OFF-DIE ADC (I've yet to see any patents from Canon involving on-die ADC of any kind)

If the ADC is still off-die, then I suspect that we will still have banding noise. I'd offer that with an improved process and higher Q.E., banding should be much less visible. That said, the 7D has one of the lowest read noise levels of all the current Canon sensors, at around 8 electrons @ ISO 100. With a better process, especially if they apply the patent that involves disconnecting the power source from charge-holding capacitors during readout, dark current could be nearly eliminated, which could lead to very low on-die noise. Once the analog signal is shipped off sensor, I really can't say what may happen. The 1D X has very high read noise (38 electrons @ ISO 100), and I suspect a lot of that has to do with the high frequency ADC's on the DIGIC 5+ chips. If the 7D has low on-die noise around 1-2 electrons, it is entirely possible off-die ADC could increase it, even above the 8 electrons we have now on the original 7D. In which case, I wouldn't expect much from low ISO on the 7D II.

In the case of the 70D, I suspect it would use a lower-clocked DIGIC chip, and probably only one. Both of those factors would probably lead to less banding. That would make the 70D more viable for all-around photography at a middle-ground FPS of 4-5. Use of the 70D for landscapes would probably be better than a higher clocked, higher frame rate 7D II. Its IQ would probably be similar to the 6D, and the IQ difference with the 7D II might be similar to the difference between the 6D and 5D III (which, from a purely sensor standpoint, leaves the edge to the 6D...same rough amount of luminance noise, but much less chroma noise.)

 

[TheSuede]

Some strange stuff in these last two pages. I don't even know where to start.

We are currently at a native ISO of 51200 thanks to the 1D X. ISO settings up to 204800, regardless of brand, are "artificial", in the sense that they are only a digital boost above and beyond the maximum native setting.

No. The actual native max ISO gain in a 1Dx is below 10,000. Anything and everything above that is digital amplification. This is still pretty impressive, since that is a roughly 100:1 ratio of gain between ISO100 and ISO10,000 - adjustable gains tend to have more inherent noise the larger the range they are supposed to cover is. Canon does NOT indicate "real" ISO's by using real numbers in stead of "Hi" and "Lo" - they indicate the cameras intended usage range. The number is just a number anyway, something that shows in a EXIF or an LCD window.
Actually limiting analog gain to ISO10,000 is a good thing - since taking the analog amplification any higher would actually hurt image performance - increase noise! - so no shame there. I'm actually quite impressed by the noise reduction they apply (but less impressed by the fact that they deny it in official blurbs). As far as I can model it it's a kind of bandwidth energy preserving color NR that works kind of like the Foveon NR system. It is however easily traceable by the noise spread from one channel to another. I have no problem with if they implement it in the "lower cameras" like the 7D replacement.

There is a finite limit to how far we can really push ISO, simply because the amount of light that will actually reach a sensor in a given very small, finite amount of time is limited.

Yes - ISO1,000,000 would mean about 18 electrons per pixel in a 1Dx (still with a bayer filter) with a perfect "100%" QE, at mid gray in the image. That's a S/N ratio of about 1:4, or -2ev - quite useless. One can usually say that the Bayer interpolation of detail gives up at about -2Ev, with most algorithms. But given true hardware-level binning.... You can get reasonable 0.5MP images out of the 135 format sensors at ISO1,000,000. With a separation-style or good quality multi-layer solution you might get a usable 1MP image.

ISO is not really a boost to sensitivity, it is simply a reduction in the white point...it instructs the sensor to register a lesser amount of charge in each pixel as "maximum saturation", or the purest color for each pixel.

Well, about. It is an instruction to the ISO amplifier, that sits as an "adaptation gain" between the sensor (pixel) Ve output and the AD-converter's V/ADU input. The sensor in itself is a fixed point, the only thing you can adjust there is pre-load voltages - something typically not done in commercial sensors.

Assuming an equal exposure value and sensors with equal quantum efficiency (i.e. equal fab tech at the same pixel size), a photo taken at ISO 12800 is going to have four times as much light on the sensor as a photo taken at ISO 51200. Because there is four times less light, at the same Q.E., the ISO 51200 photo will look approximately four times as noisy.

No. Increasing absolute exposure by 4x will decrease noise at any given point sufficiently above the electronic noise floor by 2x - not by 4x.

What happens is - taking 18% gray as a point example - that:
18% gray at some ISO has lets say a 400e- signal.
This gives a Poisson of sqrt(400) = 20 = 1:20 = 4.3Ev SNR.

Quadrupling (ISO/4) the base signal gives:
4*400e- = 1600e- of signal.
Pd of 1600e- is sqrt(1600) = 40 = 1:40 = 5.3Ev SNR

-exactly one stop less noise than the four times weaker signal, also at 18% gray.

What happens BELOW that is another matter - you've also increased your DR between 18% gray and the limiting electronic noise floor by 1Ev. If you could get to 3Ev below 18% gray with good detail at the first signal level, quadrupling the signal will give you 4 usable Ev's below 18% gray (if the AD converter and ISO amplifier noise is low enough - this is what's missing in the Canon implementations today, why they have 1.5-2Ev less DR at base ISO).

Using the 1D X as a basis, with a Q.E. of 47% it has a maximum saturation of 170e- (electrons) at ISO 51200. Assuming 94% Q.E., that would be a max. sat. of 340e-, and for 100% Q.E. a max. sat. of 362e-. Since 100% Q.E. means you are efficiently converting every single photon into an electron, that means 362 photons are captured per pixel. At ISO 1638400, you would capture a mere 11.3 photons per pixel before it saturated!

Here, you're missing out on a very basic fact about sensor properties, and how they're reported.
The QE of a sensor is reported AS IS in the construction it is applied.
This means that the 1Dx has got a QE of 47% - this means it converts 47% of the energy already filtered by the CFA. CFA filter average area efficiency is typically around 35-40%. Real incident photon energy > e- conversion rate is then about 0.35*0.47 = 0.16 = 16%... A sensor construction without color filtration would have three times the amount of photons available for conversion.
As I mentioned - the Bayer interpolation actually takes away about 2Ev of usable image detail in the end result when all factors are included. A sensor not dependent on filtration - that absorbs all the light you give it - can have more than five times higher e- per photometric exposure level than what the 1Dx has (assuming 80% QE with no color filtration, 60% within the visible band is not unusual in scientific sensors at room temprature)

The Panasonic patent (that just like all Sony Exmor patents is an implementation patent, not a base patent...) still suffers from some interpolation losses in the color interpolation necessary in the post-processing, even though it uses all available light. AND the usability is severely limited by the angle losses, effective T-stop of a F1.4 lens would be about about T2.5, even if the lens in itself was a perfect T1.4 - so the real gains are only there for F2.8 and smaller aperture lenses. Which kind of takes away a lot of the large-sensor usability. So the 100% light usage sensor is still very far away as you say...

 

[jrista]

We are currently at a native ISO of 51200 thanks to the 1D X. ISO settings up to 204800, regardless of brand, are "artificial", in the sense that they are only a digital boost above and beyond the maximum native setting.

No. The actual native max ISO gain in a 1Dx is below 10,000. Anything and everything above that is digital amplification. This is still pretty impressive, since that is a roughly 100:1 ratio of gain between ISO100 and ISO10,000 - adjustable gains tend to have more inherent noise the larger the range they are supposed to cover is. Canon does NOT indicate "real" ISO's by using real numbers in stead of "Hi" and "Lo" - they indicate the cameras intended usage range. The number is just a number anyway, something that shows in a EXIF or an LCD window.
Actually limiting analog gain to ISO10,000 is a good thing - since taking the analog amplification any higher would actually hurt image performance - increase noise! - so no shame there. I'm actually quite impressed by the noise reduction they apply (but less impressed by the fact that they deny it in official blurbs). As far as I can model it it's a kind of bandwidth energy preserving color NR that works kind of like the Foveon NR system. It is however easily traceable by the noise spread from one channel to another. I have no problem with if they implement it in the "lower cameras" like the 7D replacement.

Last I heard, Canon used two analog amplifications...one at the pixel, which topped out at ISO 1600, one "downstream", but before the ADC (or maybe as part of the ADC itself, never saw a patent), and then, for "expanded" ISO settings, it used digital amplification. In the case of the 1D X, I do not know where the per-pixel amplifiers cut off...it may still be ISO 1600, however I guess I find that unlikely given how good ISO 3200 and 6400 look. If we assume ISO 12800 is the highest the per-pixel amplifiers are capable of, ISO 25600 and 51200 would use the downstream amplifier, leaving H1 and H2 as the only digitally amplified settings.

That jives with past Canon sensors. The 7D is great up to 1600, so-so up to 6400, and terrible at 12800.

There is a finite limit to how far we can really push ISO, simply because the amount of light that will actually reach a sensor in a given very small, finite amount of time is limited.

Yes - ISO1,000,000 would mean about 18 electrons per pixel in a 1Dx (still with a bayer filter) with a perfect "100%" QE, at mid gray in the image. That's a S/N ratio of about 1:4, or -2ev - quite useless. One can usually say that the Bayer interpolation of detail gives up at about -2Ev, with most algorithms. But given true hardware-level binning.... You can get reasonable 0.5MP images out of the 135 format sensors at ISO1,000,000. With a separation-style or good quality multi-layer solution you might get a usable 1MP image.

Sure, you could probably "bin", and improve the quality. I guess if you wanted both an excellent low-ISO camera AND the worlds best low-light camera all in one, binning down to half a megapixel would be great. But binning increases the complexity if the sensor, and probably doesn't do as good a job as lower resolution sensor with gigantic pixels.

If someone is really interested in low-light photography...such as indoor events, night sky photography, street photography at night, etc. I think the best option is a real low resolution sensor that just strait up packs the photons into every pixel.

ISO is not really a boost to sensitivity, it is simply a reduction in the white point...it instructs the sensor to register a lesser amount of charge in each pixel as "maximum saturation", or the purest color for each pixel.

Well, about. It is an instruction to the ISO amplifier, that sits as an "adaptation gain" between the sensor (pixel) Ve output and the AD-converter's V/ADU input. The sensor in itself is a fixed point, the only thing you can adjust there is pre-load voltages - something typically not done in commercial sensors.

Heh, sure. I was trying to keep lower-lower-level electronics talk out of it, as not everyone here understands things at that level. I might as well put up an electronic diagram and tell everyone to have fun reading it. Trying to dumb down gain, voltages, etc. just means I end up writing ten times as many words to explain the same thing in a way the majority of people can understand.

For all intents and purposes, ISO settings above 100 simply instructs the camera to read out the sensor with a lower white point. Simplistic, maybe, but all voltages and gain and ADU's aside, that's effectively what's happening.

Assuming an equal exposure value and sensors with equal quantum efficiency (i.e. equal fab tech at the same pixel size), a photo taken at ISO 12800 is going to have four times as much light on the sensor as a photo taken at ISO 51200. Because there is four times less light, at the same Q.E., the ISO 51200 photo will look approximately four times as noisy.

No. Increasing absolute exposure by 4x will decrease noise at any given point sufficiently above the electronic noise floor by 2x - not by 4x.

What happens is - taking 18% gray as a point example - that:
18% gray at some ISO has lets say a 400e- signal.
This gives a Poisson of sqrt(400) = 20 = 1:20 = 4.3Ev SNR.

Quadrupling (ISO/4) the base signal gives:
4*400e- = 1600e- of signal.
Pd of 1600e- is sqrt(1600) = 40 = 1:40 = 5.3Ev SNR

-exactly one stop less noise than the four times weaker signal, also at 18% gray.

What happens BELOW that is another matter - you've also increased your DR between 18% gray and the limiting electronic noise floor by 1Ev. If you could get to 3Ev below 18% gray with good detail at the first signal level, quadrupling the signal will give you 4 usable Ev's below 18% gray (if the AD converter and ISO amplifier noise is low enough - this is what's missing in the Canon implementations today, why they have 1.5-2Ev less DR at base ISO).

You are actually quite correct here. I wrote "four times" far too many times in that...blog...

And yes, that is indeed Canon's problem in a nutshell....amplifier noise and ADC noise are really what kill their DR at low ISO. Based on what I've read about Exmor, the use of analog CDS circuits (and non-uniform response inherent to such a design) is also a prime source of vertical banding noise, so it is really the amplifiers, CDS, and ADC that contribute to Canon's low-ISO noise.

Using the 1D X as a basis, with a Q.E. of 47% it has a maximum saturation of 170e- (electrons) at ISO 51200. Assuming 94% Q.E., that would be a max. sat. of 340e-, and for 100% Q.E. a max. sat. of 362e-. Since 100% Q.E. means you are efficiently converting every single photon into an electron, that means 362 photons are captured per pixel. At ISO 1638400, you would capture a mere 11.3 photons per pixel before it saturated!

Here, you're missing out on a very basic fact about sensor properties, and how they're reported.
The QE of a sensor is reported AS IS in the construction it is applied.
This means that the 1Dx has got a QE of 47% - this means it converts 47% of the energy already filtered by the CFA. CFA filter average area efficiency is typically around 35-40%. Real incident photon energy > e- conversion rate is then about 0.35*0.47 = 0.16 = 16%... A sensor construction without color filtration would have three times the amount of photons available for conversion.

Hmm, I thought the Q.E. reported by the likes of DXO was "as measured", not "as is". I generally use Sensorgen.info for basic statistics like that, which I believe is based on DXO test results. I'm curious how DXO derives their Q.E., if it is, as you say, what the electronics and photodiode itself (below all the filtration and microlenses and whatnot) is capable of preserving. If it is indeed true that the Q.E. numbers reported on Sensorgen.info (which would really be as reported by DXO) are POST-filtration, then we really do indeed have a LONG way to go before truly preserving ~100% of the light that reaches the sensor through the lens.

To that end, I believe significantly cooling the sensor can greatly help improve the efficiency of the silicon underneath the CFA. I doubt we'll get to -80°C in anything we could buy over the counter, but even moderate cooling to keep the sensor below ambient could improve results, and increase Q.E. as you've described it. There was a rumor that Canon was prototyping such technology as well, which is why I have my hopes up about one of the forthcoming sensor designs from Canon...be it the 7D II or big MP, I think we could see some nice improvements in Q.E. from Canon.

As I mentioned - the Bayer interpolation actually takes away about 2Ev of usable image detail in the end result when all factors are included. A sensor not dependent on filtration - that absorbs all the light you give it - can have more than five times higher e- per photometric exposure level than what the 1Dx has (assuming 80% QE with no color filtration, 60% within the visible band is not unusual in scientific sensors at room temprature)

Aye, completely agree here. Bayer sensors literally throw away unconscionable volumes of light! The problem is, despite the losses from the CFA and interpolation, they still produce better results than the alternatives as of yet. I look forward to seeing more unconventional designs on the market in either Nikon or Canon cameras...something like the Pentax color splitter design in a Canon DSLR would make my day.

The Panasonic patent (that just like all Sony Exmor patents is an implementation patent, not a base patent...) still suffers from some interpolation losses in the color interpolation necessary in the post-processing, even though it uses all available light. AND the usability is severely limited by the angle losses, effective T-stop of a F1.4 lens would be about about T2.5, even if the lens in itself was a perfect T1.4 - so the real gains are only there for F2.8 and smaller aperture lenses. Which kind of takes away a lot of the large-sensor usability. So the 100% light usage sensor is still very far away as you say...

True, there is still interpolation, however I am not sure it suffers "the same" losses as a classic bayer design. At least as I understand the Panasonic patent, there are really only two pixel colors, which would produce a much more even grid of W-R and W+R pixels. The grid layout for either one of those has the same spatial resolution as the green pixels of a bayer array, which has twice the spatial resolution of red and blue pixels. I'd take a more evenly distributed W-R/W+R grid than a bayer array any day. Throw in some efficient cooling to reduce dark current to nearly nil, and I think such a design would perform considerably better than a bayer design.

Regarding the "angle losses", I'm not really sure what you are referring to there...so I'm not sure how to respond.

 

[jrista]

Looks like the thread has been "reset" to my last post from a day ago. Guess we can get back on topic.

(BTW, just posting this so everyone who was following this thread knows it was updated...as the recent deletions did not update it in my "replies" page.)

 

[CarlTN]

In the case of the 70D, I suspect it would use a lower-clocked DIGIC chip, and probably only one. Both of those factors would probably lead to less banding. That would make the 70D more viable for all-around photography at a middle-ground FPS of 4-5. Use of the 70D for landscapes would probably be better than a higher clocked, higher frame rate 7D II. Its IQ would probably be similar to the 6D, and the IQ difference with the 7D II might be similar to the difference between the 6D and 5D III (which, from a purely sensor standpoint, leaves the edge to the 6D...same rough amount of luminance noise, but much less chroma noise.)

Astutely observed and pondered. How do you explain the fact that the measured sensor resolution drops off so dramatically at higher ISO on the 6D, as compared to the 5D3? I have read this is so, have you? The 6D supposedly loses resolution quickly above ISO 6400, while the 5D3 doesn't see a big drop until above ISO 12,800. Of course these are higher ISO questions, but I like to shoot at higher when I can. I also like to shoot at lower ISO in good light (or longer tripod exposures), when possible...for landscape, etc.

I suppose whatever the sensor or overall processing is doing to have lower noise at low ISO on the 6D, could also be what begins to hurt it at higher ISO? No doubt this is intentional.

 

[jrista]

In the case of the 70D, I suspect it would use a lower-clocked DIGIC chip, and probably only one. Both of those factors would probably lead to less banding. That would make the 70D more viable for all-around photography at a middle-ground FPS of 4-5. Use of the 70D for landscapes would probably be better than a higher clocked, higher frame rate 7D II. Its IQ would probably be similar to the 6D, and the IQ difference with the 7D II might be similar to the difference between the 6D and 5D III (which, from a purely sensor standpoint, leaves the edge to the 6D...same rough amount of luminance noise, but much less chroma noise.)

Astutely observed and pondered. How do you explain the fact that the measured sensor resolution drops off so dramatically at higher ISO on the 6D, as compared to the 5D3? I have read this is so, have you? The 6D supposedly loses resolution quickly above ISO 6400, while the 5D3 doesn't see a big drop until above ISO 12,800. Of course these are higher ISO questions, but I like to shoot at higher when I can. I also like to shoot at lower ISO in good light (or longer tripod exposures), when possible...for landscape, etc.

I suppose whatever the sensor or overall processing is doing to have lower noise at low ISO on the 6D, could also be what begins to hurt it at higher ISO? No doubt this is intentional.

Hmm, not sure what you mean by the sensor resolution drops off. The sensor has a fixed spatial resolution, nothing can really change that. At a higher ISO, you have less light to work with, so the structure of detail may not end up completely defined...that could lead to apparent softening (well, it does...that is why noisy images from very high ISO settings tend to lack detail...not enough light to build up the structure of that detail as anything more than partial detail and noise.) However, I would expect the 6D and 5D III to perform similarly in this area. If you have any links to reviews that demonstrate teh effect, I'd like to take a look.

 

[CarlTN]

The review was in the latest issue of Popular Photography. I'm sure the noise is the factor in their resolution test (not sure if it's an "MTF 50", like Lensrentals uses to test lenses...but surely it involves some kind of test chart or target...of course that would mean the lens' sharpness gets factored in, which seems like that would be undesirable.)

Here is their test of the 5D3 from July 2012. I can't find the 6D, it's possible it's not on the website because it's in the current print issue, and they don't want it on the website yet...I don't know.

http://www.popphoto.com/gear/2012/07/camera-test-canon-eos-5d-mark-iii-dslr

Btw, I was just being sarcastic in that other thread, your pics always look great to me...I guess I just cannot abide anyone who refuses to shoot above ISO 1000...it's like they're a girly man or something! Hahaha...