I wonder how long it will take before we come full circle and are able to upgrade/ change sensor packages and sensors become like film. After all, full frame lenses have the same minimum circle of coverage by definition, as do to all APS-C and 4/3’s lenses.
Not necessarily upgradeable by the end user – sensors still require precise alignment & a dust free environment – but say by a repair shop for $300-500 - what they charge in labor to replace a damaged sensor on a DSLR. (Though a very clever inventor might develop a way to auto align a sensor.)
Then you could buy the body features you want and select from either the OEM sensors or get an after-market. Sensors could be selected on size, MP count, DR and noise without regard to body make. Sony sensor in Canon. Canon sensor in a Pentax. No different than Fuji film in an Olympus.
Frames rate would be function of the amount and location of high speed memory and the speed of the digital processing chip, more than the sensor itself. High frame rates would still require expensive high speed RAM and processors – as they do now.
Other than standardizing the sensor pin-outs and some of the firmware API calls, there’s no serious technological hurdle. All sensors are mapped arrays like LCD screens or scanners. The power and cooling requirements are all roughly the same across comparable sensors, because ultimately, they all have to work with the same size batteries and bodies.
Metering and auto focus are sensor independent.
The various image processing chips are more about the firmware than the actual semi-conductors. They all have to do the same functions. Performance appears to be mostly a matter of software - from DIGIC 3 to DIGIC 5, the chips had only a modest increase in clock speed. And as hackers have shown, the chips and software are fairly standard across a given OEM’s models – it’s only a matter of unlocking features in the firmware.
You could even go further and make the digital processing chip upgradeable, though I suspect you would have to continue using a Canon processor in a Canon body.
The obvious place to start would be the 4/3’s cameras, which already maintain standards and interoperability.
Why would the camera manufacturers do this?
It would free the body development cycle from the sensor development cycle. Since the days of film, camera makers always made money from selling bodies, and this is no different. Canon for example, could refine its bodies and digital processing in response to market demands much more quickly, without having to wait on a new sensor.
Manufacturers like Nikon already source their sensors from Sony, allowing Nikon to focus on bodies and processing software, and letting specialized companies with more resources focus on sensors. This is just another step in that direction.
Camera makers could continue to make money selling various sensor and digital processing upgrades. When you figure that most of the retail price (not cost!) of a given SLR is digital components, breaking that out into its own product line makes sense.
It also opens up the possibility of putting higher end sensors in lower end bodies. There is no physical reason why a Rebel Ti, a 60D or 7D is limited to a APS-C size sensor other than the sensor itself and the choice of prisms.