If you look at the weight,
D600 with a
85 1.8,
70-300 VR
24-85 (unstablised BTW, f3,5 to f4,5)
Weighs 2,3 Kg
Oly OM-D with:
45 1.8
45-175 Panny
12-35 Panny
Weighs 1100 gram.....Take the Gh3 and it becomes 1200 gram.
This captures the main problem perfectly. If one is happy with an M4/3 setup like this, there is no way to achieve equal size/weight in 135 format. They simply don't offer a 90/3.5 lens the size and weight of the 45/1.8 (probably cannot, even if they tried), a 24-70/5.6 the size and weight of the 12-35 (probably cannot) and a 90-350/8-11 the size and weight of the 45-175 (certainly cannot).
Well, the d600 body is 800g aprox and the 50mm f1.4g is 280g, so just over a kg?
Now, the d600 is 50mm native FX at 1.4 (nothing in the m43 to match that in dof) and in DX mode its a 75mm f2.0 (better than 45mm imo for FL) so to get this flexibility on my OMD, I need to take the OMD or GH2 and the 25mm f1.4 and the 45mm f1.8 and even then, dof is in the f3 zone not the 1.4-2.0 zone? If I was to take the three m43 items, gh2/25/45 then its about 800g as well, so I save 200g, little lighter with omd(plus its ibis) little heavier with a gh3.
The spec of the 50mm f1.4 for £250 is incredible, 9 blades, 0.4 close focus etc etc.
http://www.dxomark.com/index.php/Lenses/Camera-Lens-Database/Nikon/AF-S-Nikkor-50mm-f-1.4G/ (camera)
680 (cameraname)
Nikon-D7000
All in all the fx/dx option has changed my perception and the reduced d600 size body really makes it less intrusive with the lighter nikor primes and other options.
One day some company might put out a 135 format interchangeable lens camera the size and weight of the ME Super and that day I will consider getting into that format. OK I will not be so extreme. I will pounce when it got to Nikon FA size shape and weight.