I realise this is an old thread but did you ever figure out the answer. I get soo annoyed reading all over the internet about this problem and people replying ‘its a monitor display issue’, ‘Sorry the footage is dark’ Sorry to sound rude but no it’s probably not dark, its only dark because that footage has been captured and therefore as he said, it is dark.
I have tried everything, new monitors, new programs, new firewire, new graphics card, new codecs/no codecs, nothing seems to fix this problem. The footage is perfectly coloured/lit on cam, and on tv, but as soon as capture, bammm, dark edges, increased shadows. Every other movie plays perfectly, it only becomes darker after capture. Please DO NOT say it’s a monitor/display issue again. This is a completely different problem to that. THe captured footage has actually gained dark edges, darker shadows, a loss of luminance, a loss of colour, ONLY after capture.