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astrophotography advise please

G

grooveattack

macrumors 6502a
Original poster
Jan 9, 2008
511
1
Hey guys.
just wanted some advise.
I am going out to the country tonight to try my hand at astrophotography for the 1st time!

my plan is (and this is where i will need some help) is to point my camera up at the sky and do 30sec exposures ( long enough? )

what is the best lens to use? i have a 50mm f1.8 and a 18 - 250mm 3.5 what one is going to work best? shall i use the 18-250mm zoomed in? will that help me get 'closer' to the stars?

thanks guys!!

by the way i will be using a canon 60d on a gorilla pod.
 
The smaller the focal length, the longer the exposure you can use. Maybe at 18mm you could pull off a 30 sec exposure. I doubt you're going to get anything beyond that without getting star trails in your shots.
 
star trails at 30 sec? wow i underestimated how fast the earth spins!

so if i am going to use the zoom i might have to ramp up my ISO and do shorter exposures?
 
Actually, I usually shoot with 10 secs and that is borderline before stars become eliptic, instead of round.

this is at 24mm actually.
Also make sure you crank the IsO to at least 800 in order for the other stars and fainter stars to show up..

Look at this shot. While nowhere near great or anything, it was shot @ 24mm, 8sec exposure at ISO 2500...

I have no idea what i am seeing but that "nebula", was seen by the naked eye. more or less. Problem is that at longer exposures it got trails and les ISO , it didnt show up.

Like i said, its nothing wow but it illustrates a point, me thinks...
 

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I haven't had much experience but when I've shot the moon before it's been around: iso100 | 200mm | f/11 | 1/125. ish.
 
I'm a total noob at astrophotography, but some things I've learned so far are:
1) Use a short focal length. Any shots I've taken zoomed in just look bad. Doesn't at all look like you're "closer" to the stars. Probably makes a difference if you're on a motorized equatorial mount tripod or something like that.
2) Try to take at least some shots at the horizon so you get trees or something in the foreground. Makes much more interesting shots.
3) While it's still light out, auto-focus at an object at infinity. It's pretty tough to manual focus at night. Some lenses, you can turn the focus all the way to one end to focus at infinity, but my 24-105 L lens focuses past infinity, so it takes awhile to find the sweet spot.
4) Use a remote shutter release if you have one.
 
The nice thing about photographing stars, is that some noise can be mistaken as a star. If your photo has noise, but not too much it will just look like small stars.

Also, if you can't get enough stars without trail go with a full trail. Set the exposure to bulb, use a remote shutter with a lock, and leave it open for a while. I've taken some 30 minute exposures and at that point the star trails look good

Edit: Another thing I forgot to mention. You said you're using a 60D, so when you follow the 600/focal length rule, you need to multiply the focal length by the crop (1.6x on a 60D). So an 18mm lens would be 28.8mm 35mm equiv (18*1.6). That would mean a 20" exposure.
 
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