>>3241209You can design a significantly more compact lens for the shorter flange distance of a typical APS-C sensor mirrorless camera. With full frame mirrorless, I think Sony is the only company offering a full lens line-up for such a camera, and most of their lenses are virtually as large as DSLR lenses, so in practice, it may not be as advantageous to go mirrorless for full frame cameras. Theoretically, you should still be able to design smaller lenses for any mirrorless camera than for a DSLR, though, which is one inherent (though again, theoretical) advantage of the shorter flange distance used on mirrorless cameras.
Also, a lot of people like how you can easily adapt older manual focus lenses to short flange mirrorless cameras (an EF mount mirrorless camera wouldn't offer this possibility), but honestly, adapting lenses is overrated.
The people still adapting manual lenses on mirrorless cameras are the same people who buy a Honda Civic for $9,000 and then spend $12,000 in third party upgrades, instead of just spending $20,000 on a sporty Mazda with the virtually the same feature set that they want, and which has better reliability to boot because all of the parts are factory parts and therefore work better together as a system. It's the same deal when you adapt manual focus lenses on mirrorless--Yeah, you certainly feel special with your $450 Voigtlander Nikkor F mount lens on a $2 Chinese adaptor ring on your Sony NEX, with focus peaking flashing blue and exposure zebras flashing red covering up whatever it is you were photographing, as you carefully focus your lens, then twist the aperture ring and then finally click the shutter release. But the whole system falls apart when a photographic situation throws you outside of your comfort zone. For example, trying to photograph a puppy that's constantly fidgeting even when sitting still and running around the rest of the time. You'd be lucky to get a single in-focus photo with a manual focus lens.
