Tuesday, June 28, 2011

Long Exposure Crowd Control

  Last Thursday I finally got my IR converted Canon 20D back from Lifepixel. Since then I have spent most of my free time running around town experimenting with every subject I can imagine. I look forward to blogging about infrared photography when I have a bit more experience. But this week I have to do something simple so I can get back to IR-ing. Today I will discuss another special approach to "Crowd Control"

  From reading a number of my blogs, it may seem that I hate people. I have discussed stacking multiple images and cloning to remove those pesky carbon based life forms from my landscapes. The truth is that I only question the role of humanity  when they have the unconscious audacity to come between me and my vision.   At the risk of further damage to my social reputation, I offer one more way to nonviolently eliminate people in a special situation.

   A few years ago, I happened upon a classic cobbled street in the heart of the wonderful seacoast city of Portland Maine. Wharf Street is a pedestrian passage that gets heavy foot traffic especially on warm Saturday evenings in the spring. I found that I could capture the warm light with an exposure of about 3 seconds, but, with folks continuously walking by, the road was filled with blurred bodies. My first approach was to wait for a magic moment when the street was clear of people, but I was with friends who were increasingly impatient to get to dinner. I only briefly considered returning at 3am in hopes that the lights would still be on, but I quickly decided that a more civilized choice was to try a long exposure.  




30 second Exposure
In the second image I was able to stretch my exposure to 30 seconds, f22 and ISO 100. During that 30 seconds a number of couples walked by, but, as long as they kept moving, they disappeared.  Of course I tried to maintain an unwelcoming expression to discourge curious people from stoppping in front of the camera to ask what I was doing.  A few stationary vagrants remained in the image, but overall I was pleased with the results. This approach might have worked better with a longer exposure, requiring the use of a neutral density filter, but image noise would have become an increasing problem.



  Long exposures can be used to remove or de-emphasize moving objects or people, but, as I've tried this in other situations, I have discovered a couple of factors that can effect the success of the approach. First, long exposures work best when the background shines though for the majority of the time. Ideally this would mean folks coming through on random paths with space in-between. A long continuos line of people walking past will obscure the background with a soft blur, artistically interesting, but collectively transforming
the individuals into an amoebic blob instead of removing them. Secondly, any bright or specular light will inscribe trails on the image regardless of how long they are in view.  The streaks of colorful light created when capturing a long exposure of a busy road at night can be interesting, but it makes it impossible to hide the presence of the vehicles.  As it turns out, Portland's Wharf Street was a good place to use this technique. On the other hand, the image of Main Street in Keene New Hampshire did not work as well.  I took a daylight 30 second exposure  with a line of cars coming by. The cars were not seen individually but they produced a soft blur which was punctuated by streaks of gleaming chrome. Although I like the soft appearance of the trees, this was clearly not the best situation for this technique.

I plan to continue to experiment with this approach. I am particularly interested in trying longer exposures, up to several minutes. Anything to remove the pernicious impact of humans on our environment!

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