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Marloon
7th of March 2009 (Sat), 16:29
when people do long shutters.... is that just bulb mode and they just hold the shutter open for however long they state?

when people do 30 minute exposures, sometimes they have intervals... so do they just overlay them on top of each exposure using photoshop?

Thanks
-Marloon

chauncey
7th of March 2009 (Sat), 18:05
#1...Bulb
#2...what intervals?

Marloon
7th of March 2009 (Sat), 20:32
well some people have said that they've done a 3 hour long exposure... isnt a 3 hour long exposure really BRIGHT?! (well obviously... unless its super duper dark.. but still)

Nacnud
10th of March 2009 (Tue), 12:23
Well, I've had horribly under exposed shots with the shutter held open for 10 mins at ISO 200 and f4 with a quarter moon and some haze.
So that's 20 mins at ISO 100, 40 mins +1 stop, 80 mins +2 stop, 160 mins +3 stop.
That's 2 hours 40 mins under a quarter moon, it soon stacks up into silly exposure times !!!!

Secondly, I think you meant stacking 30 second exposures - it's the longest duration the camera will do in shutter priority mode.
It's a technique that needs experimentation, but has real potential.
Don't bother stacking in Photoshop - that's like serious effort!
Instead, have a play with the Startrails application - it's free!
http://www.startrails.de/html/software.html

jrader
11th of March 2009 (Wed), 07:19
well some people have said that they've done a 3 hour long exposure... isnt a 3 hour long exposure really BRIGHT?! (well obviously... unless its super duper dark.. but still)

Actually, not necessarily. It can be extremely bright if you have the wrong settings, but with the right settings the camera will produce images that have the "correct" exposure. I've done some long exposures at night, but none longer than about 15 minutes. Of course, I was shooting at ISO 100 and WIDE OPEN (i.e. f/4 if I recall). Now, if you want to stop down your shot for greater depth of field, remember every stop doubles your exposure time. Also, every factor of 2 in ISO adjust shutter time by a factor of 2 as well.

So say I shoot during full moon at f/8 for 3 minutes at ISO 200 to get a properly exposed shot (this is pretty close to what I shoot for night exposures at full moon). Now, stop down to f/22 (which is 3 stops from f/8 ) and lower the ISO setting to 100 lengthens the exposure time to 48 minutes for the exact same exposure. That's a lot of waiting (not to mention that in-camera noise reduction will take about as long, so total 96 minutes=1 hr, 36 min). Just for one exposure!!! But depth of field will be great. Just make sure you nail the focus before you take your first (and only 1 of 5 possible in a night) shot.

Mind you, this is all during full moon. Take into account the phases, you can figure out pretty easily how they affect exposure lengths (i.e. half moon=2x exposure length, etc.)

In reality, there are easy ways around this. I may just take the time to write a tutorial on night photography one day. Until then, just keep asking questions.

Hope this helps.

John

jsc230
18th of March 2009 (Wed), 11:32
This may not help much, but instead of stopping down to f/22 if you had a tilt-shift lens you could capture a wide DOF by tilting the focal plane. Then you could keep the aperture at f/8 and not have to wait as long

Joe Conklin
(really wishes he had the money for the new 17mm ts-e)