"The camera has an extreme wide angle of view, so when it was put on the ground facing skywards, it caught the sun on the left side of the picture. Refraction through the pinhole caused the semi-circular light image on the right of the picture. And no, I didn't know this was going to happen! Homemade pinhole camera, 70mm focal length, 8x10 inch paper negative, 8 minute exposure, Worldwide Pinhole Day, 25th April 2010"