AdamT

FWIW, Brian Caldwell, who designs the Speed Booster optics, stated on DPR that users are reporting that the EF-S 17-55 CAN be reversibly modified to work with the EF Speed Booster by removing the rear plastic shroud. 

The GH3 certainly does allow RAW shooting at 16MP in electronic shutter mode; I use it all the time.

 

Rolling shutter should be reduced with the GH4's e-shutter as the sensor read speed has been improved by 50%.  It should also be useable with ISO 3200 whereas with the GH3 it's limited to ISO 1600.

 

I have read, however, that the GH4's e-shutter files will be 10 bit only, whereas the GH3 captures 12 bits with e-shutter.

My assumption is that the A7S is reading the whole sensor in camera and downsampling to 1080p before writing to the SD card. I don't know how else they could claim that there's no binning or line skipping. If they were just reading a smaller center portion of the sensor there would be a significant crop factor.

No uncompressed 10bit 4K over the GH4's micro-HDMI port, you need the 10bit HD-SDI box for that.

This is incorrect according to multiple sources, including Pansasonic reps and the camera's manual.

It's academic at the moment, however, as there's no recorder that will do 4K 4:2:2 10 bit over HDMI.