Why is my SD card taking up so much storage?

It seems that when I load video's on to FCP directly from my SD card they take up much more memory than they should.

For example I had around 80GB of storage left on my mac and uploaded the content of my 32GB SD card and now I have 600Mb left and it's still optimising. I even had to shut down programs because there's not enough left to run them.

I'm getting a external hard drive tomorrow if I can find one compatible for a mac. But my question is why is 32GB worth of data taking up over 80GB on my hard drive?

Because when you optimize your footage, it gets transcoded to ProRes which takes up much more space. Working from your system drive is a big no-no in anyway.

Thanks,

So how do I upload straight on to an external hard drive? Also how do I work from the external hard drive? I know this is probably a really simple question but I just want to make sure I get it right.

This may not be entirely the best workflow, but I just drag from my SD card directly onto my external HD, into a folder, then import that into FCPX where it can do it's optimizing thing. You have your FCPX on your system drive but have your media folder (project & render files) on the external, which must be Firewire or better (Thunderbolt), with a spin rate over 7200 rpm (if I remember correctly).

Pretty easy: plug in your external drive and card reader, open FCP X, then create a new event on your external drive. Import your footage into this even (copy files!).

Don't forget to create a camera archive from your card.