CanonWatch summed up an IR interview with Canon and it's clear how Canon sees little value yet in offering a Full F rame mirrorless. The main issue they have is that FF mirrorless isn't really compact if you look at the camera+lens size. And certainly if you look at the Sony FE lens offerings you really cannot say they are MUCH smaller than DSLR lenses.
Yoshiyuki Mizoguchi from Canon said:
In terms of how we view the role of mirrorless, first it’s within the EOS framework that we’re talking about. There was obviously the need to pursue smaller products that were more lightweight. So we kind of view the EOS mirrorless cameras from that perspective to begin with. It’s not just looking in terms of solely as a mirrorless product, but within the interchangeable lens camera segment. We kind of view it as playing a role within that … sort of an extended view, as a means of achieving a more compact, lightweight product. There was obviously the question of whether or not, within the regular DSLR format, there was a demand for lighter, smaller products. You know, there are various approaches on that, but this is a means for us to address that issue within sort of the EOS universe.
Well let's see if Canon is just hiding their cards yet...
from Mirrorless Rumors
