I have been filming coorporate presentations / lectures / workshops with a 5D MKIII. I want to know if there is any other apparent reason of filming this kind of events with and EX1 besides the 30 minutes rec limitations.
Is it going to have any other advantage image wise? Is this going to look more professional on an EX1 or not?
You could ask in the corporate or cinematographer forums. I think DSLR's are great for certain work, if it's short-form. For presentation/lectures, I personally don't think it's the way to go. You get better, uninterrupted record times, better/easier audio, easier lens controls, in a camcorder that's a camcorder first. Nowadays, they're using the same imaging systems as DSLR's so there's less and less reason to accept the limitations imposed by a still cam platform trying to do the work of a motion camera.