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This view of Tory Island Lighthouse was made late in the evening, some time after sunset.
It was a hazy evening and I noticed that the beam of light from the lantern was very well defined as it swept across the island. I put on my headlamp, grabbed the camera and tripod and walked out halfway to the lighthouse, where I could get an uninterrupted view of it.
This is the composition I decided upon, a relatively wide view of the scene, and a long exposure to show the beam on both sides of the tower as it swept around its arc.
To prevent the lantern itself from becoming overexposed, I had to cover the lens with my hand every time the light passed over my position.