Filled about 80GB from 6 CF cards using a 7d/5d. Added the footage to my external HD. Then, I Log and Transferred my footage in FCP using ProRes422(LT). Seems like this is taking up lots of space on my hard drive. Is this normal. I know that H.264 footage is highly compressed and takes up much less space, but after using Log and Transfer ProRes422 is turning this 80GB into almost 160GB.
Sounds reasonable. H.264 is a long GOP codec - there are "key frames" (different from keyframes for animation) and then frames that note what has changed since the last key frame. ProRes (all variants) is not a long GOP codec. Every frame is independent from every other frame. Because there is far less compression going on it'll take up a lot more space.