I am currently using a RX10 M2 at the moment. I want to upgrade for the longer lens. I also have a RX100 M5.
I'm leaning on getting the RX10 M3 at the moment because it's about C$500 cheaper in Canada before tax. That's a lot of money. What's holding me back from getting the M3 is the autofocus issue. I mainly shoot landscape, seascape, travel, and the occasional portrait. The M2 fit my needs most of the time, but there are times I found 200mm to not meet my needs.
The AF on my M2 is pretty good for static objects as that's what I mostly shoot. I do find face detect/eye detect to be not very good in low light situations. It just doesn't seem to really work unless the subject is closer to the camera and the light level improves a bit. Is the M3 like this as well? I think Dpreview said the M3 have autofocus accuracy issues at the long end of the zoom. Is that shooting moving objects or static objects as well? I didn't realize autofocus accuracy can be an issue with contrast detect autofocus for static objects or very slow moving objects. Is the face/eye detect AF as good or better than the M2 in low light situation?
If it's true for the questions above, then I'll have no choice but to get the M4 even though it cost significantly more. Since the M4 have the RX100 M5's sensor, can it focus at lower light levels than the RX10 M2/M3? I don't see any indication on Dpreview that it can. Is AF on static and slow moving objects much better than the M2 and M3? How is face/eye detect autofocus in low light situations?
Can Bluetooth on the M4 be used to trigger the shutter?