[Brightcolours]

To each his own. I cannot see M43 as anything much better than the 1 inch sensor cameras, unless a miracle happens in sensor design it is going nowhere very slowly.

If you use equivalent f-values (read: similar aperture size with similar DOF), MFT is not very much different than what you get with FF. So, if you use f8 on FF, use f4 on MTF. Like I said, FF has a shallow DOF advantage as its main advantage...

APS-C iis a valid choice for certain purposes as much as FF is for others, and  has reasonible performance but using the same technology then FF will be better. It just depends on where your prefered performance is.

 

The A7 or A7r with the 24-70 / 4.0 is very different to a Canon EOS 5D with 24-70 / 2.8 or a Nikon 800E with the 24-70 / 2.8.

 

F 4.0 is quite enough for me thank you.

Not all that different from a Canon EOS 6D with a 24-70mm f4 L IS USM.