To see if you need to adjust your black and white point levels go to the Image menu and under Adjust, select Levels.
Levels shows you how the image is mapped between black and white. The spiky mountain is the amount of colours in the image, the 3 triangular arrows shows where the black mid-grey and the white are located.
In the top image (video-levels) the white-point is way below the first indication of white. This setting is typical of an image that needs adjustment. So type in 16 in the first input level box and 239 in the last. Click OK. If the levels menu looks like the lower box there is no technical reason for adjustment but often the image will improve by some adjustment. Play around and use the preview tick box to see the 'before and after' effect the adjustments make.
Bernhard Frankel is the Technical Manager for Luxonline and is also an artist working with time and technology. You can see some of his things on his website.
For more information about this see
Video Levels in Final Cut Pro by Graeme Nattress on Kenstone's Final Cut Pro website.
BBC - Commissioning - A Guide to Picture Size