Star Trails Using Lightroom and Photoshop

Discussion in 'Technical threads' started by Andy Grundy, Mar 11, 2012.

  1. [​IMG]
    Thornton Force Falls By Night by andy_grundy, on Flickr

    Things you'll need:
    • tripod
    • shutter release / remote control
    • A camera capable of taking long exposures (30 secs or more)
    • A seat
    • A friend (I presume it would be hellishly boring if you were on your own)
    • And if you're in the UK:
      • plenty of clothing layers
      • gloves
      • a big woolly hat
      • loads of socks
      • hand warmers
    Things to consider:
    • A darker sky will give you clearer stars, more stars and more possibilities to increase the exposure times so get as far away from towns and cities as you can
    • Use as wider focal length as you can get your hands on as you really want to get a sense of the scale of what you're looking at
    • Aperture - as wide as you can get it. You need to get as much light to your sensor as possible to get the most stars as you can.
    • ISO - A higher ISO will also get more light in, but be careful not to get too much noise. I used ISO500 on this one which was as high as I'd dare. I guess the law of averages would reduce any noise when the images are stacked together but I've not stretched that theory too far just yet!
    • An interesting foreground will make the photo stand out. Seeing as you'll most probably be trying to find it in the dark try and scout the location before hand so you know where you're going
    • Try and find something that is pointing north. That way you can get a good circle of stars rotating around the north star
    Getting setup and taking the shots:
    Landscape or portrait? This all depends on the foreground interest and the context you're looking for. With this I wanted to get as much of the waterfall as possible, while also getting a good balance between that and the stars so I thought portrait would be best. Once you've found your spot, and decided which format the picture will take you'll want to take a couple of test shots. It's usually way too dark to see what you're looking at through the viewfinder or live view so take some test shots and try and judge by any means possible whether you've got what you need in frame. For this I could just about see the outline of the tree on the top right so knew roughly where the waterfall would be. Once I was happy with the composition I set the camera to manual (it is manual March after all, but the camera will never be able to meter in any semi-auto modes anyway) and chose F4 (the highest my wide angle will do), 30 seconds on the shutter, and ISO500.

    After that it's just a case of pressing the remote every 30 seconds for as long as you can stick it out. In this case that was as long as it took my mate's 40d to run out of batteries (all 3 of them). Canons eh? The same AAs from the Pentax are still going strong this weekend!

    If you have a more sophisticated remote, or a timer you could probably make life easier by locking the shutter button down, setting the drive mode to continuous mode and selecting a longer exposure.

    Post Processing:
    With this sort of shot a lot of the work is done after the event. I ended up with 161 shots that I could work with. In Lightroom I selected all of these with a red flag and filtered the collection by the red flag so I only had the shots I wanted in the selection. Unfortunately, as it was so dark I hadn't realised the composition was on a massive lean so had to straighten all 161 shots. As it turns out, one of my most favourite features of Lightroom, the sync tool, will even sync the crop settings so I straightened 1 of the shots, adjusted the white balance for what looked a more natural look and synced the lot.

    sync settings.JPG

    Seeing as though I was going to be stacking all these shots together I thought I'd edit a good portion of shots to highlight the waterfall by adjusting the exposure and fill light so that the stack would average out and give a good balance between foreground and stars.

    difference.JPG

    Once these are done it's just a case of exporting all the files to be able to use them in another package to stack them. For this I used Photoshop but there's plenty of other free apps that will stack multiple shots on top of each other. To do this in Photoshop though, is actually a whole load easier than I thought it'd be. Go to file>scripts>statistics and import all the files from the export. Make sure the stack mode is set to maximum and click OK. At this point you can go and make a brew or something slightly more exciting 'cos it'll take a while!

    Eventually though, you'll get a perfectly stacked star trail which you can then import back into Lightroom to do any fine tuning. In this case I added a grad filter in Lightroom to accentuate the difference between land and sky just to give a bit more punch.

    grad.JPG

    Easy peasy. Alternatively, you could just go somewhere truly dark and leave the shutter open for an hour and half. Sadly though, Hawaii is slightly out of my price range at the moment :)
     
  2. Great write up man! Thanks!
     
  3. Question - how are you getting images backwards and forwards between LR and PS?

    When I've tried before it was easy enough to send from LR to PS but I never did figure out how to send them back. I always ended up saving a copy and then importing that into LR.
     
  4. Excellent Andy, great explanation. Cheers.
     
  5. LR doesn't do a good job explaining this but if you are in LR and you do the whole right click Edit In PS deal... once you are done all you have to do is go to File-Save and then exit PS. When you go back to LR the new edited file (TIFF or PSD depending on your settings in the preferences) will be there.
     
  6. Ah is that all. I didn't think that would work so I always used Save As to create a new file which I would then import again from within LR. It's a bit weird that within LR there is an option to send images to PS but not the other way round!!!
     
  7. @Andy Grundy I should let you know that in the last year, this has been the most viewed article on the site with over 6000 page views.
     
    Batty79 and Adam like this.
  8. Star trails is the next thing I want to try. Good info on what settings to use.
     

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