Live View Question - Does Shutter End Exposure?

[Noel_Carboni]

I've found that Live View supports astrophotography very well, insofar as not only can you adjust focus in real time, but also because the shutter is already open and the process of starting the actual exposure is fully electronic, which avoids telescope vibration.

My question is: Does Live View shooting end exposures electronically as well? In other words, does the shutter closing end the exposure or does it stop before the shutter moves? Obviously this will affect the last few milliseconds of the shot.

In the past with my 20D, I had a devil of a time trying to photograph the companion of Sirius (Sirius B), which is very, very close to the bright main star and requires short exposures, even at ISO 100. I plan to try again with my 40D.

-Noel

[ChrisPerry]

Since they say live view is great for macro work and i just got some extension tubes I thought I'd give it a try.
Hmm...it'll take a photo, but won't trigger a flash. PITA.
Also, apparently in live view it closes the aperture - I see very little DOF when in live view, but when I take a photo the DOF is more normal looking. Odd I thought.

[Dennis_Vied]

Did you try the stop-down button in Live View? Pity (or, as you say, PITA), that it won't trigger a flash. That seems strange to me.

[ChrisPerry]

I had a PW on the hotshoe. Didn't touch teh stop down button - never do as I don't see any change in DOF, things just get darker.

[Dennis_Vied]

Originally Posted by ChrisPerry

things just get darker.

Boy, do I ever understand that. Me, too.