|
If you want a long star trail in one exposure, I'd use the following as a guide:
15 minutes, ISO200, f4
1 hour, ISO100, f5.6
4 hours, ISO100, f8
For the longer shots, you'll need to take a dark a frame as well! Long exposures really build up the hot pixels but they subtract out pretty well too (can use in camera dark frame subtraction but you need the battery power and the patience to wait the same time again).
If you do short exposures and stack them together, you'll inevitably have some gap (albeit small) between each segment, and the brighter exposure in each 'sub' tends to overexpose the stars so you lose their colour. I tend to prefer the first approach now.
Phil
|