New E-M1 Mark III body arrived couple days ago and here are some first impressions and arguments why I changed my M1 Mark II to Mark III.
The physical interface is now much more like M1X, which I like very much. Separate Menu and ISO buttons and joystick. Although buttons are fully programmable, I like the buttons as they are.
Continius AF is better compared to Mark II and you can also define your own targeting areas as in M1X.
Live ND shooting and hand held high resolution mode are also as they are in M1X. And of course, you can define your own menus.
There are now 4 custom settings as in M1X, but you can also define if the camera stores automatically your latest custom settings if you change then on the fly. This is very useful for me when shooting in low light conditions.
Noise level is about one stop better. I usually use Auto ISO and in Mark II I used ISO 3200 as maximum value. With Mark III and M1X I can use ISO 6400. This is also important for me.
So why I use M1X and Mark III? Mark III is very close to M1X, but M1X has still important features: it is a very robust tool with IP classification. It is no matter if you shoot portrait or landscape, the physical interface is always the same. It has better weight balance with M.Zuiko 300/4.
When I’m shooting birds I usually have both of the bodies with me. I use Cotton Carrier harness which carries two camera bodies, usually M1X with 300/4 on my chest and Mark III with 40-150/2.8 or 12-100/4 on my hip.
And now some noise sample pics from PEN-F, M1 Mark III and M1X:
With PEN-F it is better stuck to ISO 3200.