HUGE file when trying to save question? What have I done :)

I have dragged in some raw files from the GX85 Panasonic recorded at 4k onto a 1080p timeline. 

The total file size of the imported files is 15g. After editing in the timeline and trying to export it is saying the final bounce out will be 8.1gb

This is unusual - as there are no added effects.

I did have some 3d titles in the project from FCPX but then the file was 32gb. 

Have I cocked up a setting in the camera???

3840x 2160 at 23.94fps is the file size of each clip.

Love coming your way.  

Effects and titles make no difference to the file size. All that matters is the length, the codec, and the data rate. 

Open an original file into the QuickTime player and look in the info window for the complete specifications, codec, data rate, file size. How long is your original media? How long is the finished project? What settings are you using to export?

What codec were you using for export.? The export codec chosen makes a huge difference.

Passed some Karma around.
What a fool I am - H264 is what it should be - for some reason it had switched onto Apple Pro Res.

Flummoxed I was.

Been there done that.