Micro Four Thirds and background blur

The APS-C sensor size has some advantage over Micro Four Thirds for background blur.  But that does not mean M4/3 is incapable of blur!  For this trial I will use a Tamron 17-50mm f/2.8 lens on an APS-C Canon 50D, vs an Olympus 45mm f/1.8 prime on a M4/3 Olympus E-M5.

First case is both lenses at f/2.8.  The background blur is about the same.  Why, when the Canon sensor is a little bigger?  Because the distances are all the same and the focal lengths are nearly the same.
Canon at f/28 . . . Olympus at f/2.8

Next case is both lenses wide open.  F/1.8 for the Olympus gives stronger blur.

Canon at f/2.8 . . . Olympus at f/1.8

Final case is the often cited “equivalence” situation.  Where the larger sensor is set to a smaller aperture.

Canon at f/5.6 . . . Olympus at f/4

But the Canon shot shows weaker blur.  So – when the smaller sensor camera uses a tighter frame (allowing the same  focal length) – the equivalence game becomes null and void.