ok thinking of going out one night and taking a shot of the town from along the beach - most of the shot will be dark sky etc - we are talking no ambient light apart from stars and maybe the moon.  So exposures above 5 secs are expected... apart from the obvious - need a tripod, use long exposure noise reduction, use mirror lockup, use a remote switch, i have one question:

High ISO or Long exposure: which is going to be better at producing a low noise shot? bearing in mind that each is a factor in noise production.  I am mainly concerned with the noise here - but if there are other factors like colour saturation or something that you know about please share... :biggrin:

thanks for any help.

Low ISO and long expoure

I have night shots 30 sec + @100 ISO, even without long exposure noise reduction noise is minimal.

Yes I think low ISO and long exposure is the way to go  you may find you get some effects from the stars movements in relation to the earth,  look forward to the results

you will start to see star movment on exposures in excess of 12 seconds

Long exposure, using timer or shutter remote. Just don't change lenses on the beach! You wouldn't want sand to get in to your cam would you?

Yes, agree with Simon and danob....low iso and long exp works.  My Aurora shots were all @ ISO200 with no in cam NR.

Also agree with Simon regarding star movement time.....but the other thing you may notice is cloud movement (if there are any), so take that into consideration.

Let's see your results!

Ditto to everything that has been said so far.

This thread make me feel good, because low ISO and longer exposure was my answer..

That means I actually remember something from my days of shooting film..

Yes..I'm looking forward to seeing the results as well

Well Rich i might try this with you. Thanks guys for information. Its always great to learn from such experience photographers.
Chris

I really did not know but my experience and gut feeling was low ISO and longer exposure. I suppose that came from years ago being with my dad when he tried these shots.   Glad to see that confirmed by folks who know.  Thanks...TomDart.

Yes, the stars and heavenly objects move(we move) much faster than expected. As earth turns from west toward east, the stars appear to be going west.  On the north star, the movement is circular.  Turning east is only to greet the morning sun!  I like that part.

Ok, I just finished an intermediate photographic course at the National College of Photography and the fact that each and every professional photographer said time and time again is set your ISO on 100 and leave it there - ALWAYS!!! 

So, I go with low ISO long exposure as well.  Play with your apperture though and see what the effect on any lights on your captures do.  You'll be surprised at the effect ;0)

ok, thanks guys that is a definite answer rather than conflicting answers i got when having a chat on the #photographers chat-room on Deviant... I just need a clear night now and i'll be out there...

And Zeldie - isnt the main effect more of a "twinkling" look to any light source - ie those 6 radial light trails coming from the source?

inshaala - right on!  ;0)

Zeldie, tell you professor I keep my cam on ISO 50. ;oP Seriously, the only reason you should ever go with a higher ISO is if you have to capture fast action or seriously need the shot in low light even though the quality will suffer.

Kort, most low end DSLR's (e.g. 30D, 400D, etc..) don't go down to ISO 50.

Ahhh, my fixed lens Oly trumps them once again! ;oP

Kort, I have a 20D and it doesn't shoot lower than 100 ISO.  But then, I don't - usually - shoot higher than 100 ISO either    And trust me if I tell you that my "professor" knows that there are cameras that has an ISO of 50.  Most of the students' cameras though - don't  :tongue1:

LOL, umm, just to be different, mine goes down to ISO 80, and it always stays there! :o) (FZ-7)

Wayne

50 iSO is not the important factor unless the lower ISO allows the longer  exposure the noise is not much of a factor on Canon Camera sensors even less so on newer models... But even so the results wont be as good above 400 .. Some Cameras have had to use 200 ISO as standard in order to retain some quality at 400 Here you will be to some degree dependant on the technology of the sensor which varies from maker to maker.. Having a fixed focal length or range  helps.

  In answer to those who have asked me via email or IM  You can access your lower ISO on the 5D the settings go from 100-1600  with H for 3200 and L for 50 owners of other Canon cameras can check if you have the L  setting as well as H you have the full range

well - i went out and took some shots... i took them raw and noise reduced them further and they seemed to come out ok to be honest.  But in terms of "good photo" i dont think they were, but i posted one up in my gallery because i thought it would be a waste if i didnt...check it out here:

Night shot

another type of photography knowledge under my belt, maybe next time i can improve - maybe i should invest in a tripod instead of using my camera bag

You have star movement! Beam me up....

Here are a couple of links that may be useful.  Both support the idea of low ISO.  The first deals with more than stars and the second is basically about star shots. Maybe this will help a little. It has given me some thoughts!         TomDart.

http://photo.net/learn/nature/sunmoon

http://www.danheller.com/star-trails.html#1.2

Nice star trail. My cam won't stay open that long. :)

Nikon has "bulb" equivalents for some of the cams but not all.....none are cheap.

BTW, they just posted the review of the 400D over at DPreview.com Nice cam, but no longer the "obvious choice" for an entry DSLR.