[stoppingdown]

It is odd, indeed, and totally unexpected - I was really going for m4/3 (also because of the wider lens gamma), but then I did the maths and found:

 

Nikon D5100 + Nikkor 12-24mm ƒ/4G DX AF-S = 1045g
Olympus E-M1+ Lumix G Vario 7-14mm ƒ/4 = 797g
Olympus E-M5 + Lumix G Vario 7-14mm ƒ/4 = 725g
Sony NEX-6 + Sony E 4/10-18mm OS = 568g
 
Nikon D5100 + Nikkor 18-70mm ƒ/3.5-4.5G ED DX AF-S = 950g
Olympus E-M1 + Zuiko 12-60mm ƒ/2.8-4 = 1072g
Olympus E-M5 + Zuiko 12-60mm ƒ/2.8-4 = 1000g
Sony NEX-6 + Zeiss Vario-Tessar T* E 16-70mm ƒ/4 = 651g
 
The latter combination is the one I most frequently use for landscapes, and with m4/3 is substantially equal in weigh (actually, 50/100g heavier). But even in the former combination there's a clear Sony advantage in weigh. How this happens, it's still a mystery to me, but in the end the Zuiko 12-60mm is heavy (in relative terms). The Zuiko 12-50mm is lighter, but it looks as it's optically bad from some reviews. The two Olympus look as they are the only m4/3 camera bodies whose quality is substantially equal to my D5100 (M5) or possibly superior (M1).
 

<div>Viewfinder all the way. 
 
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