short subs for HDR

bcstein12

Active member
Oct 15, 2013
25
0
Could someone give me some advice on taking short subs for HDR composition. I am using a SBIG 8300M camera. I have noticed that when I take subs <60sec my background seems excessively noisy as compared to my longer ones. I only take 40-60 subs for integration. Am I not taking enough to counteract the background noise? Should I dither every sub?

Thanks
 

pfile

PTeam Member
Nov 23, 2009
5,606
103
when you do an HDR composition the shorter exposures are only used to pull in data that's overexposed in the longer exposures, so i wouldn't worry about the background noise. what's probably happening is that there's not much signal to speak of in the background so you're just looking at read noise/dark noise in those short sub's background.
 

pfile

PTeam Member
Nov 23, 2009
5,606
103
no because as mentioned only the brightest parts of the short exposures are pulled into the fimnal image. ostensibly your background is never overexposed so there's no need to take the background from any other image but the first.