[Klaus]

For the fun of it - I've created a little illustration showing the diffraction limit in megapixels for a given aperture and sensor format (for an ideal lens). The scale is logarithmic.
That's based on 420nm (violet light) as suggested over in Wikipedia. 420nm is a bit optimistic. The human eye's sweet spot is around 555nm (green light). The megapixel limit would be lower in this case - but then you are watching images on a screen.

Keep in mind that "equivalence" remains intact. e.g. the depth of field on MFT at f/5.6 is the same as with f/11 on FF. And the same applies to the diffraction limit in megapixels (27.47mp MTF @ f/5.6 vs 27.20mp FF @ f/11 in the table below) thus you can't conclude that FF is superior in terms of real-world diffraction.

The data also explains why we usually don't include f/16+ (APS-C/M43: f/11+) in our MTFs charts. Diffraction and not the lens is the dominating factor starting at the settings.

[davethebirder]

For the fun of it - I've created a little illustration showing the diffraction limit in megapixels for a given aperture and sensor format (for an ideal lens). The scale is logarithmic.
That's based on 420nm (violet light) as suggested over in Wikipedia. 420nm is a bit optimistic. The human eye's sweet spot is around 555nm (green light). The megapixel limit would be lower in this case - but then you are watching images on a screen.

Keep in mind that "equivalence" remains intact. e.g. the depth of field on MFT at f/5.6 is the same as with f/11 on FF.  And the same applies to the diffraction limit in megapixels (27.47mp MTF @ f/5.6 vs 27.20mp FF @ f/11 in the table below) thus you can't conclude that FF is superior in terms of real-world diffraction.

The data also explains why we usually don't include f/16+ (APS-C/M43: f/11+) in our MTFs charts. Diffraction and not the lens is the dominating factor starting at the settings.

 Given the data it's clear to see that a high mega pixel FF camera is the way to go if maximum sharpness is your aim .... but I'm surprised by the large margin ..........

[Klaus]

That wouldn't be my conclusion - at the same DOF, the diffraction limit is basically the same across all formats.
It's pointless to compare across the same aperture.

[davethebirder]

That wouldn't be my conclusion - at the same DOF, the diffraction limit is basically the same across all formats.
It's pointless to compare across the same aperture.

 Is it ...... at the same DOF ?? what about ignoring DOF ??  ...... or is it because no one makes a 400 Mps sensor to take advantage of the greater possible resolution of FF ....... given there's no equivalent super bright lens on M4/3rds FF equivalent to say, the 58mm F0.95 (Nikkor) ...... 
  
 I wasn't judging the whole shebang just on DOF, just outright sharpness ...... 
 
 ......... but then what do I know ??   ...............

[stoppingdown]

ePhotozine reviewed the Sony E 10-20mm F/4 PZ G and said that the only pitfall is... “Poor f/22 performance”.

[photonius]

ePhotozine reviewed the Sony E 10-20mm F/4 PZ G and said that the only pitfall is... “Poor f/22 performance”.

Yes, one must like such reviews....

---

For the fun of it - I've created a little illustration showing the diffraction limit in megapixels for a given aperture and sensor format (for an ideal lens). The scale is logarithmic.
That's based on 420nm (violet light) as suggested over in Wikipedia. 420nm is a bit optimistic. The human eye's sweet spot is around 555nm (green light). The megapixel limit would be lower in this case - but then you are watching images on a screen.

Keep in mind that "equivalence" remains intact. e.g. the depth of field on MFT at f/5.6 is the same as with f/11 on FF.  And the same applies to the diffraction limit in megapixels (27.47mp MTF @ f/5.6 vs 27.20mp FF @ f/11 in the table below) thus you can't conclude that FF is superior in terms of real-world diffraction.

The data also explains why we usually don't include f/16+ (APS-C/M43: f/11+) in our MTFs charts. Diffraction and not the lens is the dominating factor starting at the settings.

Thanks, already downloaded for reference...