Monday, May 26, 2014

Creating star trails

One of the cool techniques with photography that I've seen over the years but have never tried was creating images where the stars appear to be streaking through the sky.  It's called star trails and it's a technique that takes a lot of time.  When I set out to attempt this technique on Friday night, I followed the instructions that were listed on this site.  I have Photoshop CC and I downloaded the trial of Adobe Bridge which are two of the required tools to use.  For my subject, what other then something like the grand old Zoar Hotel.  Here's a rundown of what I did.
My first bit of advice for anyone attempting this is that if you're going to do this, be prepared to invest a lot of time doing it.  I spent about 30 minutes trying different compositions of what I was going to try and capture.  I also spent time trying to figure out what aperture and ISO setting that my Canon T3i with Canon 28-135 lens would work best.  I decided upon  f/5.6 at ISO 800 with a 30 second exposure.  I also switched from shooting RAW to JPG.  As I knew I was going to be shooting for 2 hours, I was going to end up with a lot of images and having 240+ images to process, the 25MB file size of each would chew up a lot of hard drive space.  Shooting JPG gave me 4MB files that are easier to manage.  I would also advise that when doing this, have a really good shutter release cord that locks and most importantly, a good, sturdy tripod.  If you get vibrations during your exposures, it will show up.  Also, make sure you put your camera into multiple exposure mode so when your shutter release cable is locked in shooting mode after each 30 second shot, it instantly takes another.  So with everything locked in, I started my capturing at 11:13 PM.  The next two hours seemed like an eternity.  When I was done, I came home, loaded the images into Adobe Bridge, (following the steps from the website link above), and came up with this result.
While it looks cool, I'm wasn't happy with the focus.  While it appears that the hotel is lit up, it's actually very dark.  So dark that my auto-focus on my camera couldn't lock on to anything, so I had to guess.  So that fueled me to give it another shot on Sunday.  But, I did a few things different.
First, I used a different lens, my Sigma 10-20 mm.  Secondly, I locked in my tripod even more by adding weight to it to stabilize it further.  Third, I made sure I was far enough away from the hotel to manually focus my lens to infinity and adjusted the aperture to f/6.7.  With those changes made, I started my new round of 2 hour, 30 seconds exposures. I was much happier with the results.
Using the wide angle lens gave it a much mode dramatic effect.  But, if you are familiar with the hotel, you will be able to tell that the color is off.  The only thing I can attribute to that is the green given off by the street lights and the multitude of colors given off by the passing cars.  This time however instead of using Adobe Bridge to edit the file, I edited the files in Adobe Lightroom and then used Bridge to migrate the files to layers in Photoshop and go from there.
So there you have it!  I probably will attempt more of these, but am looking for subjects that won't be as effected by other lights as much as this was.  Still, it was a fun exercise even if it did leave me a bit sleep deprived this holiday weekend.

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