ben_r_ wrote in post #13332935
Yea Im not sure you can do that as Macs automatically go to sleep once the lid is closed unless its on AC power. And was the USB hard drive you were originally thinking of using an SSD?
No it wasn't, the SSD thing just kind of crossed my mind midway through that last post. 
SpeedyGoo wrote in post #13332954
it depends on your power settings your mac book would most likly be set to turn hibernate on lid close you can set them so that closing the lid will have not change on function but really would do you much better to get bigger cards and use something similar to a hyperdrive to backup...
also what size card are u filling?
I just upgraded to a 50D and all I currently have is a 4GB Ultra II CF.
The instance I was talking about I had my Xsi with a 4 and 8 GB SD card. I was able to dump them at halftime into my macbook luckily.
Whats this hyperdrive you're talking about?
Rolfe D. Wolfe wrote in post #13332960
Honestly at the pain and expense youll face in either direction, just get a decent size mem card and shoot accordingly(i.e. RAW/JPG)
ben_r_ wrote in post #13332987
This is my advice as well. OP, you mentioned you are switching cards every hour or so, what size cards are you using? You can get yourself a 32GB Sandisk Extreme UDMA for around $130.
Yeah, it sounds like it will be cheaper just to save for a larger CF card.
My thought process was that it would have been cool to use my MB or something so I could unload pics while I shot into folders so they were easy to proccess later. Like at the game I dumped images after pregame, first qt, second qt, halftime, third qt, fourth qt post game. I had to visit my macbook set up in the lockerrooms each time to dump files.