How many darks is "enough"?

[SteveL]

I know, its the same as "how long is a piece of string", but for those of you who take darks, how many do you take for each exposure setting you have used during the session?

[Robd]

Rightly or wrongly 1.

My stacking software will only take the one. Must have a word with the author as to the benifits of taking more.

[MikeD]

I always go for 10, not sure if thats a good thing or not( seems to work well for me).

I do 10 darks, 10 flats and 10 bias frames.

The thought behind it is 10 averaged will reduce random noise in the darks ect.

[SteveL]

OK, darks I understand and use right now (I take 10 as well), but what are flats and bias frames?

[SteveL]

OK, my bad...

Bias - http://www.users.zetnet.co.uk/pete/Biasframe.htm

Flats - http://www.hiddenloft.com/ccdap3/help/hs210.htm

[MikeD]

Thats them

[daz]

IIRC from my Ian King imaging course, the darks exposure time should match your lights - i.e. they are the same duration, qty, ISO, temp etc.