Good to hear the problem's solved.
This is now getting off topic, but I'd like some advice/comments please. I've never actually used LiveView in any real way. So here's what I need to know:
I want to go out and photograph star trails, you know the kind, several hundred shots stacked to make to final image. Now if I set my camera for 30second exposures, continuous shooting and lock my cable release, it'll obviously keep taking shots until a) I tell it not to or b) the battery runs out.
The question: If i use LiveView to focus and avoid all those nasty tremors and slaps, will the screen stay on all the time and drain my battery? Can I tell it not to stay on?
I'm shooting a 7D.
What you should do is switch to manual focus, focus manually via life view and then turn off the LCD during actual shooting. You don't need life view or mirror lockup for long exposure, so off the LCD which will preserve battery power and reduce the heat generate by the LCD (improve noise performance).
As the 7D has a top display, so while taking the photo in live view, the rear screen will display nothing.
However, astro photographers normally uses stacking in combination with a motorised equatorial mount - that way each shot will be of the same bit of sky with no motion blur of the stars, and the stacking software puts the frames together to reduce noise and increase the detail of the stars.
Star trail photos are made with very long exposures - just put your camera in bulb mode for that type of shot.
The ideal way of taking Star trail is to use a single long exposure via bulb mode, but using DSLR, we can take the digital way... by taking many part of the trail using shorter exposure and then combine them together to form a single trail... the different is not obvious if you plan it carefully, the lens is wide enough and you don't 100% pixel peek. The advantage of this method is that you can limit the noise and you still can take a long star trail if your sky is quite light polluted.
Anyway, IMHO, 30s is still a bit too short for this type of shooting unless he don't have an external timer controller.
Have a nice day.