Big Megapixel Camera in 2014

[jrista]

@Mike Risedal: Thank you for sharing! I am not a tech and non-anglo as well. But do I understand correctly, that Sony sensors apply kind of a black frame ( as we do it in long exposures at night) to get rid of all the noise before ever a new photograph is taken? Well, this allows much more noise free high ISOs then...So, when is it likely that Canon apply a similar system? My 5D3 seems to be a good investment until they are able to present a similar solution.

Every camera applies CDS, or Correlated Double Sampling. The point of CDS is to determine the reset dark current noise present in the sensor, before an exposure is taken. The charge of each pixel is registered and saved, and when the actual exposure is read out, the registered reset charge is subtracted from the exposure charge. That, effectively, eliminates noise caused by dark current present in the sensor at reset time. That is a moderate mount of noise, and exists in all sensors. It is not, actually, the worst form of electronic (read) noise, so CDS only does a partial job of removing noise in hardware.

At the moment, as far as I know, Canon only employs analog CDS, via circuitry in each pixel. The use of an analog register makes their implementation of CDS succeptible to heat, charge leakage, etc. So it is not perfect, and the registered dark current noise can be "infected" by other sources of noise. Sony Exmor, on the other hand, employs Digital CDS. A reset read is performed via CP-ADC after each exposure, clearing the sensor. CDS is still employed, however instead of registering the reset charge of each pixel in analog form in CDS circuitry, each pixels reset charge is read, converted via the ADC, and stored digitally in a memory bank per column, associated to each pixel of that column. Since the reset charge is stored digitally, it is effectively immune to infection from other sources of noise such as current leakage, heat, etc. Again, that is only part of the story.

Other sources of noise, which tend to produce more prominent noise, are the ADCs themselves, and output differential from multiple ADCs. Additionally, if the ADCs are off-die, then the analog signal from the sensor itself has to travel along a bus, which can introduce its own noise. The general concept with Exmor is to turn analog information into digital information as early as possible. Digital information is bits, 1's and 0's, which are more "resilient". Error correcting data channels can transmit digital information in a reliable manner via, say checksums, and if a chunk of digital data is received that does not have a matching checksum, then it can be resent. Thus, a digital signal is always "pure". An analog signal can be "infected" during transmission, and thus can never be truly "pure".

It also aims to do so in as highly parallel a nature as possible. High frequency components tend to generate more electronic noise, and when you have fewer ADC units, each one has to process more pixels. By hyper-parallelizing the ADC with its CP-ADC patents, Sony is able to run each ADC at a much lower frequency, since each one only had to process, say, 4000 pixels (one column) rather than 4000 * N. Say, in a 6000x4000 sensor, there are only 16 ADCs...that would be 6000 columns / 16, or 375 columns processed per ADC...a total of 1.5 megapixels per ADC. An ADC responsible for processing 1.5 million pixels per readout needs to operate much faster to be capable of processing at a high enough rate to support the frame rate of the camera, than an ADC responsible for processing 1/375th of that much (4000 pixels).

By switching to a CP-ADC approach, and converting the analog signal to a digital signal at the earliest possible opportunity, Sony Exmor has made their readout more immune to infection by noise. They leave the shortest window of opportunity to allow noise to be added to the signal, this eliminating the majority of it "by default". Additionally, slight differences in ADC operation can cause banding. I have not read any explicit indication that Sony CP-ADC does this, but I believe each ADC is able to determine differences with its neighbors and eliminate any non-uniformity related noise as well (and, thus, reduce banding to a level where it never exhibits in their images.) Other forms of NR could also be performed digitally, such as PRNU (pixel response non-uniformity). The use of low-frequency parallel ADC also eliminates a prime source of heat (high frequency ADCs operate at a higher temp), thus reducing thermal contributors to noise.

Can Canon get around this patent? Well, as Mikael states, sure...they could bucket rows instead of having one ADC per column. Is that good enough? Well, parallelization is only part of the story. The real source of the low-noise operation is the DIGITAL NATURE of Exmor sensors. Column-Parallel is really more of a speed thing than a low-noise thing...by reading each column out in parallel, you can do more work in less time at the same frequency as an off-die ADC that processes 375 columns. If the on-die ADC's operated at double, triple, quadruple the frequency they operate at now in say the D800 sensor, you could achieve extremely high readout rates. You would also experience an increase in noise, however thanks to the Digital NR it is unlikely that even a higher frequency CP-ADC would produce as much noise as purely analog readout systems.

Whether Canon can get around Sony's patents for Exmor really remains to be seen. A lot of the same concepts can be employed via analog readout...column-parallel read, CDS, non-uniform response normalization, etc. could all be employed in an analog version of CP-ADC on a Canon sensor. But such a readout system would still be an analog signal, and still succeptible to infection by noise during transmission from the sensor to the image processor. Canon might be able to combine an image processor right onto the sensor die, or stack them. That would reduce the transmission distance. It would also likely increase heat, and heat is a contributor to noise in an analog signal. I dunno...at the moment, it seems like Canon is in a tough spot to really directly compete with Exmor. They could probably compete with other manufacturers using various forms of bucketed parallel readout...20 rows per on-die ADC, stuff like that. They will still experience banding (as the Nikon D5200 does), but it would certainly be a step in the right direction, and hopefully a significant improvement over their current sensor technology.

[LetTheRightLensIn]

24mp x 10fps would require 1dx's pipeline so its highly unlikely, even 24x8 would be kinda farfetched but it might be forced if the competition steps up. That would drive the whole APS pro category to 2K pricerange across the brands and the signs sofar from both camps point to a more conservative generation, i guess we'll see..

Why?? 7D did the same as the 1 series throughput?
Did it make it cost $6000? No. Digics cost dollars.

that 6k must be 2k i suppose? Eitherway keep in mind that msrps were 1.7k for 7d & 5k for 1d4. Its 7k for the 1d5 1dX, plus consider Canon's pricing trend for the last 2 years

My point was that it is not crazy to expect that sort of throughput from a 7D2 when even the 7D did it and no it did not force the 7D to cost anything close to 1 series prices.

[jrista]

24mp x 10fps would require 1dx's pipeline so its highly unlikely, even 24x8 would be kinda farfetched but it might be forced if the competition steps up. That would drive the whole APS pro category to 2K pricerange across the brands and the signs sofar from both camps point to a more conservative generation, i guess we'll see..

Why?? 7D did the same as the 1 series throughput?
Did it make it cost $6000? No. Digics cost dollars.

that 6k must be 2k i suppose? Eitherway keep in mind that msrps were 1.7k for 7d & 5k for 1d4. Its 7k for the 1d5 1dX, plus consider Canon's pricing trend for the last 2 years

My point was that it is not crazy to expect that sort of throughput from a 7D2 when even the 7D did it and no it did force the 7D to cost anything close to 1 series prices.

Ditto. I don't really see any difference between the 7D's likeness to the 1D IV and the potential for the 7D II's likeness to the 1D X. The use of dual digics and high frame rate will not make the 7D II cost as much as a 1D X. The 7D II may indeed cost around $2100, but that is the price we pay for the continual advancement of technology...newly released products rarely start out at the ending street price of their predecessors.

[LetTheRightLensIn]

Well D800 already does 4fps at 36MP in 2012 so two years later it is not crazy to think you can get a 6fps 39MP 5D4.

This is the pixelrate discussion that I wanted us to steer into.

If we assume that the fundamental technology improves yearly (e.g. Moores law), then one might predict at which speed the pixelrate will improve in the future. This is probably the case for the digital image processing (raw->jpeg development): ARM processors (according to wikipedia, DIGIC is based on OMAP, using ARM) are progressing on a steady pace wrgt speed, heat, etc.

Canon have reportedly used the same process technology for years in their large image sensors. This means that they cannot take advantage of Moores law if I am right.

There may be other factors that does not improve at anywhere near Moores law. You want a shutter mechanism that flaps a substantial mass 12 times a second while not shaking the camera enough that any increase in MP count is effectively negated unless the camera is bolted to solid rock? You want to comply with RF requirements (and avoid cellphones killing image quality)? You want to have optical path tolerances that allows AF to focus the lense accurately at 40 MP (I have just spent a few hours AFMA-ing my 7D with lenses).

-h

Moore's doesn't apply to sensors but it does to digics and the memory buffer chips and all. Yeah at some point the shutter becomes an issue but a 6fps shutter is hardly a big deal for FF, not like the 5D3 doesn't do it already or that tones of other FF cams haven't done 6fps easily. WHo is saying more than 12fps for the 5D4?? And for 1 series the 1DX already does that.

40MP FF is still LESS density than the 7D so it hardly needs AF to be even more accurate (and the 5D3/1DX and the newest lenses DO have more precise AF anyway).

[jrista]

Well D800 already does 4fps at 36MP in 2012 so two years later it is not crazy to think you can get a 6fps 39MP 5D4.

This is the pixelrate discussion that I wanted us to steer into.

If we assume that the fundamental technology improves yearly (e.g. Moores law), then one might predict at which speed the pixelrate will improve in the future. This is probably the case for the digital image processing (raw->jpeg development): ARM processors (according to wikipedia, DIGIC is based on OMAP, using ARM) are progressing on a steady pace wrgt speed, heat, etc.

Canon have reportedly used the same process technology for years in their large image sensors. This means that they cannot take advantage of Moores law if I am right.

There may be other factors that does not improve at anywhere near Moores law. You want a shutter mechanism that flaps a substantial mass 12 times a second while not shaking the camera enough that any increase in MP count is effectively negated unless the camera is bolted to solid rock? You want to comply with RF requirements (and avoid cellphones killing image quality)? You want to have optical path tolerances that allows AF to focus the lense accurately at 40 MP (I have just spent a few hours AFMA-ing my 7D with lenses).

-h

Moore's doesn't apply to sensors but it does to digics and the memory buffer chips and all. Yeah at some point the shutter becomes an issue but a 6fps shutter is hardly a big deal for FF, not like the 5D3 doesn't do it already or that tones of other FF cams haven't done 6fps easily. WHo is saying more than 12fps for the 5D4?? And for 1 series the 1DX already does that.

I don't see the 5D Next getting 12fps. It just doesn't really make sense, and unless bandwidth from the sensor to the digics can be improved, there would either need to be a third digic and a broader bus, or maybe digic 5++.

The 12fps frame rate of the 1D X did require a redesigned mirror-box and mirror actuation mechanism. The 14fps bonus rate requires mirror lockup. Lot of fairly cutting edge technology there, which again seems to diminish the prospects of a 5D Next getting an ultra high frame rate.

[Rick]

Canon would be wise to release a hi-res 5 series alongside any 1 series release, you know, so that they can sell some meaningful number of units.

[dilbert]

What will the four lenses be?

1. 200-400. confirmed by many sources and recently an interview. It IS coming.
2. 14-24. Seems likely as the wide angle is where Canon is hurting lots.
3. 50/1.4 or 50/1.8 IS USM? This lens is widely known to be weak wide open. Or the 50/1.2 but that's very young.

After that.. it becomes guess work.

Replace the 17-40 or the 16-35? Both are very week wide open and at 17/16mm respectively.
Replace the 100-400?
Replace the 24-105? It is a very weak "L" lens and newer cameras will need something better for a "kit" lens. Or will it be replaced by the 24-70/f4 as the kit lens?
Another??

[neuroanatomist]

Another??

L versions of the TS-E 45mm and 90mm.

[jrista]

Another??

L versions of the TS-E 45mm and 90mm.

Of all the lenses out there, I really think these puppies need an update, along with becoming L-series glass. They are decent lenses for what they are, but really out dated at this point.

[pedro]

@jirista: Thank you so much for taking your time to elaborate your explanation for me. Now I got a faint idea of what it is all about. I highly appreciate that! Has  there leaked any info (patents) that Canon are changing to the CP-ADC approach sometime soon? or let's say within the 5DIIIs or 6Ds body cycle? Could the rumored 5DX contain at least some first components towards this system? Looking forward to read about CP-ADC approaches related to future canon sensor designs....Cheers, Pedro

[tcmatthews]

There is one issue I have not seen here that could be holding up Canons announcement.  That is at the write speeds discuses here it is unlikely that CompactFlash or SD cards can handle the write speed.  Canon is a very conservative company they could be exploring the successor technologies for CompactFlash.  CFast which is based on serial ATA, or the other one which is based on PCIe buss. One problem is both of these technologies are incompatible with CompactFlash pin layout.  What to do create a camera with 3 card inputs? CFast, CompactFlash, SD?

They are probably using this time to see which technology comes out on top and update a number of lenses to handle increased sensor density.   It is only a mater of time before CompactFlash is completely discontinued.  It is already becoming more and more a niche product.

[meli]

24mp x 10fps would require 1dx's pipeline so its highly unlikely, even 24x8 would be kinda farfetched but it might be forced if the competition steps up. That would drive the whole APS pro category to 2K pricerange across the brands and the signs sofar from both camps point to a more conservative generation, i guess we'll see..

Why?? 7D did the same as the 1 series throughput?
Did it make it cost $6000? No. Digics cost dollars.

that 6k must be 2k i suppose? Eitherway keep in mind that msrps were 1.7k for 7d & 5k for 1d4. Its 7k for the 1d5 1dX, plus consider Canon's pricing trend for the last 2 years

My point was that it is not crazy to expect that sort of throughput from a 7D2 when even the 7D did it and no it did force the 7D to cost anything close to 1 series prices.

Ditto. I don't really see any difference between the 7D's likeness to the 1D IV and the potential for the 7D II's likeness to the 1D X. The use of dual digics and high frame rate will not make the 7D II cost as much as a 1D X. The 7D II may indeed cost around $2100, but that is the price we pay for the continual advancement of technology...newly released products rarely start out at the ending street price of their predecessors.

Agree, thats what im saying in my original post; The 7dmk2 costing as much as a 1D was a misunderstanding from LetTheRightLensIn

[LetTheRightLensIn]

I don't see the 5D Next getting 12fps. It just doesn't really make sense, and unless bandwidth from the sensor to the digics can be improved, there would either need to be a third digic and a broader bus, or maybe digic 5++.

Neither do I. My point was that it wasn't crazy to expect 6fps with a lot of MP though from a 5D4.

[jrista]

I don't see the 5D Next getting 12fps. It just doesn't really make sense, and unless bandwidth from the sensor to the digics can be improved, there would either need to be a third digic and a broader bus, or maybe digic 5++.

Neither do I. My point was that it wasn't crazy to expect 6fps with a lot of MP though from a 5D4.

I know. I was agreeing with you, and reinforcing your point. ;P

[neuroanatomist]

Can't we all just agree to agree?