Star Pictures with a Nikon D80

[tornados_blow]

This may have been discussed already, but I was wondering what the best settings are for taking star trail pictures.  I have played around with doing this with some mild success, but I wanted to take a little bit of the guessing game out of it.  I realize that one of my limitations is my lense.  I have the small 18-55mm and the small 55-200mm. 

I know that the D80 has bad amp glow and if you have a good way to get rid of that let me know.  If I turn on long exposure noise reduction it does reduce the effects of the amp glow, but it takes forever.

I'm mostly just wondering about:  ISO, F-Stop, and Shutter Speed.  Any other tips are welcome.

Thanks in advance!!!

[SA Bill]

Try this tb:
http://www.startrails.de/html/software.html

Take many short exposures (less amp glow) and the software will stitch them together. The hard part is figuring out how to tka e many short exposures automatically.

I haven't tried this myself...my star trails were all shot on good old Ektachrome film. I'm using a DSLR now but haven't tried this software.
   Bill

[Sotol Vista]

the best settings are about ISO 800 (maybe 400 if 800 is too noisy). Turn OFF any in camera auto noise reduction functions.

Manual focus and use the lowest f stop (3.5 for your lens??) use the longest shutter speed you can with out seeing any signs of amp glow.

like bill said you can take many shots and combine them with software, this will give you a much cleaner and darker background.

but do NOT let your images go for more than about 45 seconds between shots as you will have gaps in the star trails....

James

[tjavery]

With the amp glow problem, you might be better off stacking multiple exposures. However, I've seen this done and gaps in the star trails can still appear (even when shooting with the long exposure noise reduction mode turned OFF). Perhaps that was some user error (i.e. just waiting too long between shots)? But, I trust JamesB's advice. He's done a lot more night shooting that I have :-) I guess what I mean to say is that you might want to practice this method first, before you get out for the serious shots.

Regarding shooting at a high ISO, I'd advise you to step out in your backyard tonight and take several test shots at varying ISOs. I'm not sure how well the D80 handles high ISO noise, but it might be okay at 800, or it might not. It would be best to take the shots and do a comparison to see for yourself.

For general star-trail shooting, regardless of noise issues, here are two great articles that discuss shooting techniques and settings:

http://www.naturescapes.net/102007/jh1007.htm
http://www.naturephotographers.net/articles0407/ab0407-1.html

Also, this thread on NSN disucsses amp glow in various camera models (but it probably doesn't matter at this point since you already know your D80 has the problem):
http://www.naturescapes.net/phpBB3/viewtopic.php?f=1&t=139131

Here are two examples of star trail shots that I've successfully pulled off:


Canon 1D mark II, 17-40mm f/4L, no filter
17mm, f/5.6, 2815 seconds (~47 min.), ISO 200
(long exposure noise reduction engaged)

This was shot during a quarter moon about 3 hours after sunset in the Hill Country. The view is centered on Polaris. The exposure in the untweaked file was so bright that it looked almost like mid-day. I darked the exposure in RAW processing about 2 stops. The final result is what you see above.

The camera used did not have noticeable amp glow noise. The resulting image was buttery smooth.

Here's the second shot:


Canon 20D, 17-40mm f/4L, no filter
40mm, f/5.6, 1731 seconds (~29 min.), ISO 200
(long exposure noise reduction engaged)

The shot above is looking roughly south. This is from Dominguez Springs and looks over the Punta de la Sierra. This was shot in a moonless night about 2.5 hours before sunrise. The exposure was right-on. I did not lighten or darken it during raw processing.

The 20D did have quite noticeable amp glow noise. You cannot see it much in the pic above because it's been down-sized for web-sized viewing. I did print this out at 7.33x11", and you can definitely see the noise. It's annoying. I did employ some noise reduction in raw processing, but probably only at about 50% setting. Too much postprocessing noise reduction will kill fine detail and basically erase the faintest star trails.

You might want to shoot 2/3 to 1 stop smaller than your largest aperture. The reason for this is to get better sharpness AND increase your depth of field a bit. One big issue with wide-field astrophotography is getting your focus just right (manually, of course). Simply moving your focus ring out to the inifinity mark often does not work well, and it will be too dark to focus accurately through the viewfinder (unless something really bright is visible, like the moon). Increasing your depth of field just a bit will give you a little tolerance for getting the stars in good focus. If you include some land elements in the frame, you'll definitely want a little more focus depth. The two shots above were both at f/5.6.

If your camera has live view, you can focus using that. It's very accurate.

Good luck!

[tjavery]

Here's a great video tutorial on night photography:

http://www.tmelive.com/index.php/articles/view/29/16.html

One really good tip I got from this video is that you should take a test shot before the "serious" shot. Turn up your ISO all the way, open you aperture all the way, and turn off the long exposure noise reduction. Once you get your exposure just right in the "test" shot, then calculate the exposure for the serious shot.

For example, say your test shot produces a good exposure with these settings:
30 seconds, f/2.8, ISO 1600

So, you then want to do a serious (high-quality) shot at a lower ISO and smaller aperture (and turn the long exp. noise reduc. back on). Just do the math based on your test shot, and you'll have these possibilities:

240 sec., f/4, ISO 400
480 sec., f/4, ISO 200
960 sec., f/4, ISO 100

480 sec., f/5.6, ISO 400
960 sec., f/5.6, ISO 200
1920 sec., f/5.6, ISO 100

The reason for doing a relatively quick test shot is that night shooting is pretty hit or miss regarding the exposure. You can do a series of "serious" trial-and-error shots, but the long times required for the shots mean that you'll be spending a whole lot of time awake and outside in the dark. For every XX minute exposure, you'll have to wait another XX minutes for the long exposure noise reduction to run. (for example, the 47 minute exposure I posted previously occupied the camera for 2x47 minutes; i.e. it was a full 94 minutes before I could take another night shot!)

[tornados_blow]

Thank you for all the help.  Now I just have to process it all and come up with a "plan" for how and what I want to shoot.

I was looking at the moon phase times and it looks like I will have a full moon to deal with.  Hopefully there will at least be sometime where it is below the basin mountains where it won't interfere too much.  Although it will probably still affect the sky quite a bit.

If I have any luck next week, I'll post a link to some of my results.