generally videos are darker when transfered to your computer. a lot of times what may appear to be excessive light in your lcd display is the perfect amount of light. on the flip side as in your situation, what appears to be perfect light in your lcd is just not enough when transfered to your computer. I've been doing video for 3 years, have spoken to numerous people about it... and while I'm sure there is a reason behind it all.... nonetheless that's just how it is.