Friday, January 30, 2009

Long Exposure in Day Light

lillie park blowing wind 3

Camera: Canon EOS Digital Rebel XTi
Exposure: 0.3 sec (3/10)
Aperture: f/22
Focal Length: 18 mm
ISO Speed: 100


To convey the windy day outside I wanted to show these reeds moving in the wind. This can be a difficult subject to photograph when the sky is completely clear on a Sunny day. Here are some things that have to be put in place for an image like this to work.
  • Reduce Distracting Elements - This is very important, but more so with an image that shows movement like this. Had I shot this directly head on instead of shooting up toward the sky; movement would have been much harder to separate from the background. The distracting elements could be reduced by opening the lens up to F1.8 or 2.8 however, this is not possible when showing movement in direct sunlight.
  • Slow Shutter Speed - Stopping the lens down to it's almost maximum will more then likely be required depending on the amount of wind present outside. You will also want to shoot at your lowest ISO possible 100 or 50 if available. If I was to shoot head on everything in the background would be in focus and sharp since the lens is stopped down so much. Since objects further away move a smaller distance on the film plane due to the Parallax effect they would be sharper then the foreground reeds which are moving. The eye would naturally want to look at the background since it is sharper then the foreground and the moving reeds would just turn into a distraction at this point.
  • Neutral Density Filters - Even with your lens stopped down your shutter speed may still be to fast to show movement. In this image I had to use my neutral density filter ND2 which stops the available light reaching the lens by 2 stop. I would have liked a ND4 in this situation since it was very bright outside but ND2 was acceptable. You can also use a polarizing filter stack with your ND filters or alone to further reduce the amount of light available.

Post Processing

Since I had to take this image during the day time due to the local terrain where these reeds were located this image taken during the sunset would not have worked. The reason behind this is the sun sets behind a hill located behind the camera. It would have cast a deep shadow over the reeds. Some external lighting would be required to show movement and a flash is to fast in this situation. A continuous lighting source would be require which is to cumbersome to carry in the field.

I was able to replicate a sunset using a simple gradient, some masking and a hue adjustment. Viloa! This is a situation where post processing was the only option to get what I envisioned in my minds eye.

Here is another image taken the same considerations in place without a sunset sky added using photoshop.


lillie park blowing wind 2

Camera: Canon EOS Digital Rebel XTi
Exposure: 0.5 sec (1/2)
Aperture: f/22
Focal Length: 18 mm
ISO Speed: 100

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