Star-trails

[Ed Blagden]

I am off on a trip to North Eastern Kenya in a few weeks and want to shoot some star trails.  I'll be hundreds of kms from the nearest city, the skies are generally clear at night, so conditions should be perfect.  I did this a few years back using slide film and the results were great.

However, I don't know if I can do this in Digital.  I tried a couple of 30 minute test exposures yesterday - bulb setting, lens cap on, camera in a bag, and the results are truly horrible!  See below:

1.  With Long Exposure Noise Reduction Off

[attachment=22898:_MG_3363.jpg]

2.  With Long Exposure Noise Reduction On

[attachment=22899:_MG_3364.jpg]

Both are full frame jpegs, not zoomed in at all.  I have not applied any noise reduction in Lightroom, but I can assure you it doesn't make much difference even with luminance and colour cranked up to 100.  In the field I would want to keep the shutter open for several hours, so I guess the result would be even worse.

Is there anything I can do, or do I start hunting for a roll of Provia 100F and my old EOS 3?


Ed

[chex]

try taking multiple shorter exposures and stacking them?

safari njema mzee

[Luis Argerich]

Expose for the foreground, something like 1 minute at ISO400 F11 for example. Take as many exposures as you want, for a 60 minutes star trails take 60 1 minute exposures. Then you can use a program such as startrails.exe (free at startrails.de) to merge the exposures and create the trails. You'll have less noise and the exposure wont' be ruined if something happens (airplane, flashlight etc)

Luck!

[BobFisher]

Shoot RAW, rather than JPEG, whatever method you want to use.

[Ed Blagden]

Expose for the foreground, something like 1 minute at ISO400 F11 for example. Take as many exposures as you want, for a 60 minutes star trails take 60 1 minute exposures. Then you can use a program such as startrails.exe (free at startrails.de) to merge the exposures and create the trails. You'll have less noise and the exposure wont' be ruined if something happens (airplane, flashlight etc)

Luck!

Thanks Luis (and Bob and Chex).

All in all this sounds like a lot of tedious work.  Last time I shot star trails on slide film my workflow was: open shutter; go to bed for 3 hours, close shutter; go back to bed; admire ones own work when it eventually comes back from lab.  Much led arduous than sitting in the dark taking 180 one minute exposures!  I think for this application, and this alone, I will choose film over digital.

Bob - I realise that my writing was not clear in my original post.  The samples I posted were captured in RAW (I always shoot RAW) and converted to jpegs in Lightroom.

Ed

[BobFisher]

Ed, you can get an intervalometer that will allow you to set up the series of 1 minute shots and run the sequence automatically.  Canon has them.  There are third party options as well.  Phottix is one brand.  Promote Control is a terrific device as well.

[BenGreaves]

Ed, you can get an intervalometer that will allow you to set up the series of 1 minute shots and run the sequence automatically.  Canon has them.  There are third party options as well.  Phottix is one brand.  Promote Control is a terrific device as well.

I second that.  The intervalometer will let you keep a similar work flow to your slide film days.

[BenGreaves]

Ed, you can get an intervalometer that will allow you to set up the series of 1 minute shots and run the sequence automatically.  Canon has them.  There are third party options as well.  Phottix is one brand.  Promote Control is a terrific device as well.

[BenGreaves]

Sorry.  Didnt mean to post twice.

[Paulo Bizarro]

Ed,

I know where you are coming from, having faced the same problem. I used to shoot 4-5 hour star trail exposures in slide film, no problem. With digital, it's a different story. Does not mean it is worse or bad, just different. Actually, in some instances is better, since there will be no reciprocity failure, for example.

I shoot nightscapes with my 5D MKII and 24 L MKII (I prefer this lens, because the fast aperture helps in collecting more light and in capturing the fainter stars). Normally, I am using ISO 800, 30 seconds, and f/2, or f/2.8. I have't tried star trails yet, but it seems relatively easy to shoot with an intervalometer and stack the exposures later. Make sure you take a few dark frames, there are softwares that will use them in the stacking process to abstract noise (the already mentioned startrails.de is one I am planning to use).

[Ed Blagden]

Ed,

I know where you are coming from, having faced the same problem. I used to shoot 4-5 hour star trail exposures in slide film, no problem. With digital, it's a different story. Does not mean it is worse or bad, just different. Actually, in some instances is better, since there will be no reciprocity failure, for example.

I shoot nightscapes with my 5D MKII and 24 L MKII (I prefer this lens, because the fast aperture helps in collecting more light and in capturing the fainter stars). Normally, I am using ISO 800, 30 seconds, and f/2, or f/2.8. I have't tried star trails yet, but it seems relatively easy to shoot with an intervalometer and stack the exposures later. Make sure you take a few dark frames, there are softwares that will use them in the stacking process to abstract noise (the already mentioned startrails.de is one I am planning to use).

Hi, reading this and others I was thinking to myself "oh no, not another gadget to buy" (i.e. the intervalometer).  Apart from the cost, there is also the non-trivial issue of getting hold of one.  I live in Kenya, we do not have Amazon here, international shipments get held up / stolen in customs etc.

But then, I took a look at the Startrails.de site and it turns out you don't actually need an intervalometer.  A regular cable release will do.  All you have to do is to set the camera to continuous shooting, set exposure time to the max (30 seconds on my 5D), lock down the cable release, and the camera will take a continuous series of 30 second exposures until you tell it to stop (or until the battery runs out or the CF card fills up).  Ingenious!  I wish I'd thought of that.

If the sky is clear tonight at home, I'll give it a try-out.

Ed