Unlike traditional photography, (film or digital), the shutter speed in photomode does not affect the amount of light in your picture. The only difference the shutter makes is to alter the time of the exposure, ie. fast moving objects relative to the camera become blurred when a long exposure is used:
This is useful in GT4 for creating the impression of speed, where as a fast shutter speed 'freezes' the action - but keeps everything that is in focus pin sharp:
The only control that affects the brightness in GT4 is the 'EV' control - effectivley a bracketing control, allowing you to lighten/darken the image (with corresponding loss/gain of contrast).
As has been said in previous posts, there is a difference in how a television and a PC monitor interpret the images - I think this is because of differing gamma levels used by the two display methods.
As a rule I usually have to bracket my shots +0.2 - 0.5, although this is only a rule of thumb - and I tweak the pictures further in PS, including a bit of saturation to the colour if the picture requires it.
Having said this, I try to take pictures where the light is most suitable for the subject - if I want the car to stand out I will avoid placing the car in the shadows, or shooting with the sun behind the subject.
I hope this is some help to people
