Star Trails

[grizz2534]

I just recently started taking photos hard core. I was heading to rural ND and MN and decided it would be a great time to try to get some star trail pics. This one I took about 30 feet from out campfire and used it's light on the trees (hence orange trees in July) Our fire died after I took some other shots of the stars over the lake, so I didn't get another chance to try this shot again. Ah well, maybe next time! .


This one could have easily been my favorite, had it not been so grainy and dark :-/ I took another one http://www.flickr.com/photos/grizz2534/5911498130/ that was brighter, but out of focus. So now all I need to do is meet somewhere in the middle. Any tips for ISO, aperture, focusing at night?
Camera: Canon Rebel XS
Aperture value: f/22
Focal length: 18 mm
Shutter speed: BULB 992 sec
ISO: 800


Thanks again in advance for the help!

[Doug Sundseth]

Interesting subject. A few suggestions:

First, I'd recommend using a flashlight to autofocus, then setting the lens to manual focus and leaving the focus alone while shooting. Your hyperfocal distance* at f/22 is a bit over 2.5', and even at f/5.6, it's only about 10'. Nearly any focal distance will give you a sharp image throughout the field of view.

Second, I'd recommend using long-exposure noise reduction (assuming you didn't here). Long exposures will heat your sensor and increase sensor noise, which will be exacerbated by high ISO.

Third, I'd recommend opening up your aperture and reducing your ISO to match (assuming you want the same exposure time). Since you said you want a bit brighter image, I'd try the same exposure time, ISO 100, and f/5.6, which would give you about 1/3 stop more light.

Finally, for noise reduction, I dearly love Lightroom 3 (and I've heard the same from others, so it's not just me.) It handles both monochromatic and color noise brilliantly. (This has been an uncompensated endorsement, more's the pity. )

* See Online Depth of Field Calculator for a very useful DoF calculator.

[grizz2534]

Thanks! Next time I get a chance to take a picture like this again I'll have to try those tips!

D

[grizz2534]

IMG_4905 by grizz2534, on Flickr

Dropped the ISO down to 200, tried 100, sky was nice and dark, but not enough stars came through, might try later at night next time. Also I focused either on the moon, or a street light very far way, worked good for the stars. Will have to use the flashlight technique next time on the trees! I need to look into some photo editing software, but being an unemployed college student puts a damper on any major investments.

Thanks again,
D

[Doug Sundseth]

I understand that there's a special on the GIMP (GIMP - The GNU Image Manipulation Program) for poor college students. This applies to college students with little money and to college students who aren't very good (it's a two-fer). Of course it also applies for everybody else, but that just means it's inclusive.

Sorry, it's early. GIMP is free and open-source and does much of what Photoshop does.

HTH

[grizz2534]

Very cool! I'm going to check it out!

Thanks
D