How can I reduce size of video files on a Sony XDCAM? I bought a decent camera (Sony XDCAM) however I have a problem with the output file size.  The .MTS files it makes work fine in my editor, and they create the quality I need, but the 2 gig per 10 minute of footage file size is killing our transfer time.

The quality of my end product is nowhere near this so I know I am shooting way way over the top for what I need to achieve my desired end product. 

I look at the settings and I see 1080/50p PS, FX and FH
or 
/25p of the same as above FX and FH
or
720/50p FX, FS and HQ

I want to film seminars from the back of the room using the zoom ring on the lens. 

All works ok, but the 2 gig per 10mins is killing us. How can I reduce the file sizes to a more workable size?
For $495 you can cut things down to 500MB/10 minutes (or perhaps even less, depending on compression parameters): https://www.blackmagicdesign.com/products/h264prorecorder