Long exposure -- how to avoid "over-exposure"?

[Eric217138]

Do you do any time of hot pixel subtraction on your long exposures? I can see several hot pixels even on 10 second ISO 400 exposures.

• Eric

 

[Jason Hutchinson]

I've done it (well not forever) and the photo is entirely white
except a few dead pixels.

What were you taking a photo of?

I feel asleep while I was letting my camera take a bulb exposure of an old barn by moonlight. It was nice and cold that night, it would have made a nice 10 minute exposure but instead it was about 3 hours I think.

Exposing the night sky for 4 hours will yield a photo with plenty
of dark area, right? The sensor doesn't sense light unless light
hits it, right?

It should, as long as the hot pixels don't kill the exposure. The 1 series had dark frame subtraction which helped. I can't recall if the 20D and 350D added dark frame subtraction, but the 10D, 300D, and D60 didn't have it.

Jason