Blackmagic Cinema 4K has a
9.0MP Four Thirds (19 x 10 mm ) sized CMOS sensor . On the other hand, Olympus E-PL1 has a
12.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features Truepic V processor.
Below you can see the Cinema Camera 4K and E-PL1 sensor size comparison.
Sensor Size and Resolution Comparison image of Blackmagic Cinema 4K and Olympus E-PL1 Cameras
As seen above, Olympus E-PL1 has a 1.2x Larger sensor area than Blackmagic Cinema 4K. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Blackmagic Cinema 4K
or the
Olympus E-PL1 ,
including hyperfocal distance.