It is all down to sensor technology and processors. Fuji, Nikon, Sony, Canon (Samsung ??) Pentax APS-C cameras. I see more small Nikon and Canon entry level/consumer cameras than anything else. Yesterday my wife and I shot India Bike Week and , as usual, I photographed most people I saw with cameras. I did not see another Fx camera or MILC . I did see many Nikon and Canon small DSLRs, a few Bridge , a few P&S , uncountable Mobile phones, and one bright orange Pad(could have been an Ultrabook)
. The day before I did see a Biker with a Sony A DSLR.
The silent shutter on the EM1 (latest FW) is very nice to have feature. My wife used it (with 12-40 2.8 ) to shoot a school's musical event but not any dancing so the shutter speeds were low for a reasonably dark venue. It will be very interesting to see how the a6300 works with the electronic shutter. Most interested to see if there are any negative trade-offs as with the silent shutter in the a7RII. I am not expecting the D500 to be a low light/high ISO champion but If it beats the D700 I would be most happy
.
FWIW, I wound up shooting the D750 ( approx. 450 clicks) and the Df (approx. 75 clicks) almost exclusively . The a7II really did not cope with the rapid action coming from all sides (35 clicks). There was plenty of light so any of my Dx bodies would probably have coped. I had never really planned on using the Sony for action events. I was disappointed that the dust was so bad I did not get to try out some different lenses. I really wanted to use the Voigt 15 f4.5III. I should have had it mounted to begin with. Bikers love to have you shoot them on their bikes , fun verbal and non-verbal exchanges
Back to the subject
the new Sigma would not have been a lens of choice at that Focal range . I would have been better off shooting the 24-70 2.8 and 70-200 2.8 but I cannot handle that weight for 3 hours of standing these days
. The 24-120 f4vr and 85 1.8G were fine.