Thank you for your comments, some interesting comments here.
I did not consider the D810 or D850, they are significantly heavier than my D600 and slightly bigger too. I prefer to use a smaller, lighter camera, although there is no doubt the D8xx cameras are outstanding.
The D750 is an interesting option I had not considered. It is the same size and even marginally lighter than the D600. The tilt out screen would be useful, and newer EXPEED processor should give improved high ISO performance. Although I don't have many AF lenses the wider spread of AF points would be useful even for manual focusing. The D780 is rather expensive right now but could also be an option.
The Z6 is probably my first option among the mirrorless cameras. Maybe the Z5 would be better since it accepts SD cards, but the EVF is lower resolution and the it does not have a BSI sensor so high-ISO performance is not as good (not that I shoot at high ISO often, but having more head-room would be useful).
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Hi Roland!
Speaking of actuations, your D600 is still in its prime... My own D600, bought when the D600 came out, has reached 59000 actuations and it's still alive and kicking! But that's nothing compared to other cameras I own, just mentioning the ones with higher actuations:
D300: 78K actuations
D2H: 125K actuations
DF: 178K actuations
D3: 365K actuations
D2X: 692K actuations
and then D810 36K actuations, Z7 18K actuations, D500 10K actuations, Z6 5K actuations, ...
So your decision to maybe change your current camera should not be influenced by actuation numbers... that would be the last issue!
But let's go back to possible cameras replacing your D600. I will be comparing only what I have or have used
As an example, let's compare D70 vs D600 vs D810.
D70: very light, very limited at high ISO, difficult to use unchipped MF lenses (no non-CPU menu)
D600: midweight, better at higher ISO, has non-CPU lens menu
D810: heavier (but rock steady al low shutter speeds), even better at higher ISO, has non-CPU lens menu
[I'll assume that the D850 has improvements to nthe D810 both in High-ISO and resolution. Of course it weighs more, it's a small fee to pay!]
Let's kick in the Z6 and Z7
The Z6 (and Z6 II) has the same resolution as the D600 (24MP), it weighs 675 grams vs 850 grams of the D600
The FTZ adapter's weight is not listed in your table, so I did measure my own FTZ: 136 grams, (without caps)
Z6 (and Z7) + FTZ: 811 grams, you save 39 grams
for completeness, Z6II (and Z7 II): 707+136=841 grams, you save 9 grams
So, weight is a non-issue for Z6/Z7 (or the II versions) vs the D600
Let's compare high ISO, vibration reduction, and viewfinder
high ISO: the Z6 is a clear winner
viewfinder: if you compare side-by side a Z6 and a D600 in night conditions, the Z6 (and Z7) allows you to actually see the scene, while you have to guess the framing on the D600 (it's always too DARK to tell). This is because of the light amplification of the EVF (
very useful!)
viewfinder zoom: no such thing on the D600, very useful and practical on Z6/Z7: you can map the zoom-in/zoom-out function to a Fn button. I find myself using my MF lenses a lot more now that my eyesight is not-so-good and I can zoom in (even on screwdriver lenses such as DC-105 which can be used only in MF). Additionally: if you clip in a DX lens, you will have the full image in the EVF, not a small portion of the image surrounded by a red line
Vibration reduction: on Z6/Z7 you have in-camera vibration reduction even for MF 1959 lenses, no such thing on the D600. On a dedicated Z lens, you have even more sophisticated VR, not even dreamt of on the D600...
One problem with D850, Z7 and Z7II is image size, it will slow down your workflow. On the practical level, you don't need a 47MP sensor all the time...
My opinion? Go for a Z6 or a Z6II and be happy!
Ciao from Massimo