I think Canon has been milking it for too long on the Digic 4. That sensor was awesome when it came out in 2007. But that was 4 years ago. They need to release Digic 5, and it better be awesome for making people wait 4 years. Companies like Apple, Dell, Intel, etc... release a significantly improved processor every year, and it boggles my mind that Canon takes 4 years to update theirs. That is insane in this day and age where tech advances every day.
Even Panasonic with their GH2, updated their processor in 1 1/2 years. Even though the GH2 sucks for stills, for video it took a leap over the Canons.
I think for the stills guys, the processor updates are not that important, but for the video guys, we want more and better and soon.
I *really* wish people who clearly don't understand the role processors play as it relates to noise wouldn't post such nonesense. The noise on the Canon sensor has nothing to do with the Digic. The Digic will only post process that noise away.. that's what is known as cooking the RAW. Canon as a rule does not do any noise suppression on RAW data, hence the Digic is meaningless as it relates to noise.
Digics will *never* be more powerful than a full blown CPU/GPU in a modern computer, and even they can't process away the noise on the sensor to look like Sony's latest.
Please stop suggesting that Digics have *anything* to do with noise in an image, especially when we're talking about RAW noise from DXO. I'm not sure what you *think* these processors do, especially when shooting RAW, but I can tell you they pretty much stream bits from the sensor onto the storage card. For RAW that's about it. For JPEGs they must do much more work and the same is true for video, *that* is where a new Digic will have an impact. But even a Digic 6 won't out process my PC, and it will never produce the quality I get from third party tools that take minutes to run noise routines. Even with those tools my output isn't better than a D7000.
Canon's next sensors will just move the bar. The same way their 18mp sensor moved the bar. It's been a game of leap frog for a long time now and it amazes me how people lose sight of this. Sony (not Nikon, not Pentax... SONY) made a great sensor this time around. In fact the sensor race seems down to Sony and Canon right now (Nikon's inhouse APS-C sensor wasn't ready/good enough for the D7000). I say *good for Sony*. It will just push Canon forward.
There is no magic, no secret sauce when it comes to sensor performance. Both these companies have access to the same academic research papers. Both the companies have the resources to implement those technologies. Both these companies have patent libraries so deep neither could possibly infringe on the other without a counter suit infringement being available. In short; other than generational differences due to different release cycles expect similar levels of performance from similar generations of sensors. In 1.5 years a new Canon sensor will be better than a 1.5 year old Sony sensor, I'd bet good money it.
All that said, the Digic has *nothing* to do with it. Canon hasn't released a new Digic because they haven't needed it. You will get a Digic V in the next FF cameras, but only because the MP count and video requirements need it. Up until now it hasn't been needed and offered nothing had it been available (it won't improve video quality by itself, Canon's sensors can't read fast enough to read the entire sensor 60 times a second to downsample in post, hence the skip-line/skip-column approach). Without a much faster set of readout circuitry there was/is no need for a new Digic.. period.