Monday, November 3, 2014

Following the stars

Canon 70D, Sigma 10-20mm lens, shot at 10mm, ISO 1000, 30 second exposure

Since May, I have been on a quest.  If you follow me on Facebook or on the blog here, I've made several posts about making star trails.  Star trails is a photographic technique where you take multiple shots of the night sky over a period of time, merge them together and have the final output produce an image where the stars are shown moving through the sky while the objects in front remain still.  Doing this takes a lot of time and patience.  For the most part, at least 60-120 minutes of the camera securely mounted on a tripod taking multiple 30 second exposures.   It's a really cool effect and is actually a lot of fun, (at least for me), to produce.  After a lot of trial and error, I've finally figured out the right combination to create this effect and generate some good results.  And being that I have blogged many times in the past for my "day job" to share information, I figured I would do the same here to share my steps and hopefully inspire others to take a dip into this!
Like many other things in photography, there are different ways to achieve an outcome.  But for me these are the tools I use to generate this effect. Tripod, camera, shutter-release, Adobe Bridge, Adobe Photoshop and Adobe Lightroom.
  1. Tripod - I cannot say enough about having a good, sturdy, well built tripod to help achieve a proper outcome.  Make sure everything is locked down tight.  One night when I was doing this, I discovered when I got home that one of my tripod legs was not tight and I needed to repair it. So make sure before hand that everything is good and tight!
  2. Camera - A good DSLR can really make the difference.  I've recently upgraded from a Canon T3i to a Canon 70D.  Really a nice camera.  I also shoot RAW when I do this. I started out shooting in JPEG mode but I found that I loose a lot of detail and also the final outcome looked very fuzzy.  So like for anything else I shoot, I recommend RAW.  Use it for this too!  Also, make sure your camera is in multiple exposure mode.  Meaning that as long as the shutter button is held down, the camera will continue to take exposures.  
  3. Shutter-release: Many tutorials I've read online suggest using a piece of tape to lock down the shutter button.  Don't waste your time.  Spend several dollars on Amazon or eBay and pick up one for your camera.  More importantly, one that you can lock down so it tells the camera to keep taking pictures!
  4. The Adobe trifecta - Bridge, Photoshop and Lightroom.  More on this in a bit.  You can get away with just Bridge and Photoshop if you prefer to edit in there, but, I like Lightroom better for final edits.
So with those tools in place, here's the steps to create one for yourself.  Now be prepared to fail.  I did and it took many hours of trial and error to get this right.  So let's go!

Taking the shots
  1. Find a place that's dark.  If you have a lot of light pollution, it can effect your outcome.  Also, I found it best to shoot on a night without the moon unless it's REALLY clear, meaning no haze. If the moon is lighting up the sky and if there is a thing layer of hazy clouds, the moon will light up that haze and block out the light from the stars.
  2. Once you find a good spot, set up your tripod and like I've said previously, lock everything down tight!
  3. Get you camera mounted on the tripod, hook in your shutter release and line up your shot.  It's best to try and use the autofocus at first to make sure your in focus, but then switch to manual focus.  
  4. Set your ISO anywhere between 800-1600.  
  5. Set your shutter speed to 30 seconds.
  6. Set your aperture to somewhere around f/6.7-f/8.  Remember, the smaller the number the wider the opening and more light hitting your sensor.  But also, the smaller the number, the less sharp it can be.  I've found f/8 at 1000 iso has been working for me.
  7. Take test shots.  Lots of them.  Zoom in on the back display and look at the detail to make sure things are in focus.
  8. Once you have things set up, look at your watch and note the time.  Then start shooting.  Like I said, I usually go for anywhere between 60-120 minutes.  
  9. Sit back, and look at the stars.  There's not a lot else you can do at this point.  
  10. When your done, carefully unlock the shutter release and get that last exposure.
  11. Now, but the lens cap back on the lens, set the shutter speed to something like 1/30 of a second and take two shots so that you have two blanks shots.  This will be used later.
  12. Now that you have all your shots, pack up your gear and head home.  You've got some computer work to do! 
  1. Now that you're back home, connect your camera to your computer and copy over all the shots you've taken to your work folder.  Include the two blank shots.
  2. Once the copying is complete, open Adobe Bridge.
  3. Navigate in Bridge to your work folder and you should see all your shots displayed on the screen.  In Bridge, you could edit the first picture and then apply the edits to all your other shots.  I HIGHLY recommend not doing that.  In my trials I found that editing shots in Bridge first causes a lot of odd things to happen.  
  4. Now select all the pictures in your work folder, including the two blank shots.
  5. Once they are all selected, go up to the Tools menu, Click on Photoshop and select "Load Files into Photoshop Layers"
  6. This will launch Photoshop and start the process of taking each individual shot you've taken and create a layer in Photoshop with that image.  This can take a while and is dependent upon your computer processor and memory.
  7. Once all the merging is complete, select all the layers, including the blank images.  Once selected, click the drop down in the Layer menu where it says Normal and click Lighten.  This will then merge all the layers into a single image.
  8. Once that's complete, DO NOT EDIT yet.  Save the file.  If you want to save it as an Adobe file, you will need to select Large Document Format.  That will generate a HUGE, multi-gigabyte file.  I recommend saving it out as a PNG file. You can choose whatever compression you want, but I select Smallest/Slow and None for interlace.  That generates about a 120 or so MB file.
  9. Once the PNG is done, that is the file you will edit.  You can either open it in Photoshop or edit in Lightroom.  In Lightroom I correct for the lens, edit color, contrast, etc and save it to a JPEG from there.
  10. Like I said before, don't edit before you get to this point.  I had tried editing in Bridge first in the past, correcting for color, lens, etc and had some really odd mosaic effects coming out in the image.  Resist the urge to do it in Bridge.  Wait until you get a single merged image, then edit.
  11. Once your editing is complete, save out the file and share it with others!  Also, look closely at it and decide what you could do better next time.  
So that's my basic cookbook.  Oh, in case your wondering why I kept saying copy over those two blank shots.  I read a blog that suggested it to help combat noise on the final merged images.  I saw a huge improvement with that simple step.  So, get out there and try it for yourself!  

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