Canon and high 46 Mp camera. What is going on?

Started Oct 6, 2012 | Discussions thread
aus_pic_hunter
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Re: For $9,000 who cares?
In reply to bobn2, Oct 7, 2012

bobn2 wrote:

aus_pic_hunter wrote:

bobn2 wrote:


Nikon doesn't seem to have had to choose - it provides both low ISO and high ISO DR. So why did Canon have to choose one or the other? And, if this new technology is round the corner, why did they not put it in their flagship model? After all they have had as long to develop it as Nikon and one has to assume that the 1D X is their best shot.

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Bob

This is very common for Canon. You regularly see features in lower speced cameras before they end up in the top models. The first Digic 5 was not used in a DSLR but a P&S. They put a HDMI connector on a xxxD camera first, not on the 1Dx. GPS and WiFi is in the recently announced 6D, not in the 1Dx.

Those are a completely different class of feature. For a start they are not Canon developed technology. The Digic 5 just means buying the next iteration of the DaVinci application processor form Texas Instruments, and in fact those come loaded with features such as HDMI out and GPS and WiFi integration (because they are designed to drive mobile phones and tablets) so Canon simply decides how much of the mobile phone infrastructure they build in, buy the RF and driver chips from whoever makes them and off they go. The sensor is the core and is Canon developed tech - at least it is the route that Canon takes. Them you have to judge how they are doing against the commodity manufacturer (Sony) and other companies doing their own R&D (Nikon) - in both cases they are falling short.

You are missing the point. They may be a different class of features to you but they are the ones that are in the specs and they are not in the top model so why would this be different for the sensor? Sensor development finishes way before the camera is announced. Maybe as much as a year earlier and for a complex camera like the 1Dx even more. A 1D has a very long development cycle. In the meantime development continues and an improved sensor may be in the next DSLR which is not their top model.

I don't call Sony a commodity manufacturer. I'm also wondering who made the Nikon designed sensors. Nikon is a fabless company so it is definitely not Nikon. I bed it is Sony [they are the biggest sensor producer in the world] and so they [Nikon] would be using Sony technology.

Technology is marching on and you have to set a deadline for development or you will never ship a camera. There is always something new that you might want to include too. This is a fact of life for product development. I do get the feeling sometimes that in Canon different design teams work on different cameras and these teams very rarely talk to each other. One thing for instance that mystifies me is why Canon choose to develop three different FF sensors for the 1Dx, 5DIII and 6D while these sensors are so close in specs. It would be much cheaper to put the same sensor in all three or I must be missing something.

Technology does not march by itself, it is the result of R&D programmes. The 1D X performs essentially the same as the D3s did two years ago - it looks pretty much like Canon's R&D team spend two years equalling Nikon's, while Nikon and Sony moved on - there is little gain to be had on the low light end, why everything has ended more or less equal - so they put the development in the absolute DR. This is the issue, why is Canon unable to deliver in the core technology, the bit it keeps under its control - and the context of the thread is that it would actually do better if it just went with the commodity product.

And that is a pretty good achievement. The D3s is a very good camera with a great sensor. Achieving the same quality while adding more pixels is good progress. Plus there is more to a camera than just the sensor but let's keep it to that.

One thing to add to the 14 or 16 bit ADC debat. 14 bits is more than plenty, 16 bits is overkill. What Canon's real problem is is that they have a higher noise floor than Sony because Sony solved the precharge variation problem. This causes the Canon sensors to exhibit pattern noise levels (banding) that is higher than that of the Sony sensors. And that's why Sony sensors do 14 stops DR at low ISO and Canon only 12 stops. Sony's approach of the column ADCs on chip makes that compensation easier to implement than when you have off-chip ADCs.

The read noise of the pixel amplifiers is very similar looking at the curves at higher ISO levels.


The 'precharge variation problem' - I presume you need reset noise? That is one reason Sony is doing better, but there are plenty. Another is that their 14 bit ADC's are delivering close to 14 bits effective, while Canon's are delivering about 12. The subtext to the 16 bit ADC is that it might deliver 14 bits effective, and it would be fine to save that as a 14 bit file. If Canon had available commodity ADC's that delivered 14 bits from a 14 bit width, at the speed they need to use - that would be fine, but it looks like they haven't.

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Bob

If the circuitry is designed properly an ADC can resolve close to its specified resolution. It is true that at high speed you may loose some resolution but 2 bits is a bit much or it is poorly designed.

Anyway if you don't get the input noise level down, adding more bits in the ADC is not going to help you. 14 bits is plenty with the typical noise levels coming from an image sensor.

I agree that unless there are some serious technological breakthroughs we are getting close to what is possible with todays technology. BSI sensors for DSLR may improve things a little but they are terribly difficult to produce for full frame.

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