Sunday, August 19, 2012

Black Terns

 Photographing birds in flight is a challenge.  They fly by fast, it is hard to get the camera and lens to focus on your fast moving target, it is tricky to get a fast enough shutterspeed to stop the motion.  But it IS a fun challenge.

During my last two visits to Brazoria National Wildlife Refuge, I was seeing terns and gulls flying near me.  I have not studied terns enough to immediately identify them as they fly swiftly past me.  So, I wanted to photograph them to help me study their markings in order to identify what I was seeing. When you have a photograph, you can connect with other birders to confirm your guess.  But, getting that photograph . . .

My birding lens is a Sigma 300-800mm lens that I purchased before the price got so high. I also bought a strong tripod and a Wimberly Gimbal Tripod Head to be able to support the big lens and to get the most benefit from it.


The Wimberly head allows me to track birds as they go up and down in flight as well as to pan as they fly by. Sometimes I feel like Luke Skywalker on the Millenium Falcon as I try to pan with the bird's flight, get the focus on the bird and attempt the shot. I use AI focus which helps keep the focus on the bird in flight. But there are elements of both skill and luck in getting the focus on the bird and the shot taken before the camera focuses on something else. There are a lot of images that are destined for the trash folder, but with practice you can get images certainly good enough to make the identification. Sometimes you even get some good behavioral images as well.

These are black terns in their non breeding plumage.

Note the gray wings and the black smudgy spot right above the breast (under the wing) as well as the dark spot right behind the eye. 

In trying to capture the images, I was just shooting away.  But it was luck that I caught this shot in this pose.
You don't have a lot of time to frame your photo when you are shooting just to capture the bird in flight, so it is fun when you get the reflection as part of the image as well.

When I shoot birds, I generally shoot shutter priority.  In this case I started at 1/400, but decided that wasn't doing a good enough stop motion.  I bumped it up to 1/640 for these shots. I then set my ISO for the lighting conditions to get a good exposure at the optimum shutter speed.  With the muted early morning sun, it was ISO 500 for these shots.

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