When you read about 'DIGIC', 'BIONZ', or 'EXPEED' in dedicated digital cameras, you're on the spot with custom processors. (In some cases, more than one) They're often multi-chip modules that can be scaled depending on the level of camera and can be based on standard SoC or embedded macros.
On top of that, you'll have the 'firmware', which is where projects such as Magic Lantern/CHDK make things fun.
On top of that, you'll have the 'firmware', which is where projects such as Magic Lantern/CHDK make things fun.
Some reading on the Canon gear:
http://cpn.canon-europe.com/content/education/infobank/captu...
http://magiclantern.wikia.com/wiki/Datasheets