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Canon EOS M first-look preview: Digital Photography Review
"The EF-M mount is 58mm in diameter, with a flange distance of 18mm from the bayonet to the sensor. As the image above clearly shows it's matched specifically to the APS-C sensor size. So don't expect a future full frame EF-M mount camera - it's not going to happen".

Te styki w bagnecie EF-M wyraźnie wskazują, że nie znajdzie się miejsce na FF.