This blog is a collection of images that show all directions at once. The images are created by combining a sequence of 4 photographs shot with a fisheye lens in four different directions. That is, shoot North, rotate 90 degrees, shoot East, rotate 90, shoot South, rotate 90 shoot west. This process of shooting 4 photos takes about 40 to 60 seconds because the camera needs to be level in 2 planes and you need to rotate the camera around the entrance pupil of the lens so that the images "fit together" exactly.
After the 4 fisheye images are "stitched" together (I use PTgui Software to do this) the result is a equirectangular image like the thumbnail photos on this blog. These equirectangular images are a single rectangular image that shows all directions at once. They look a little funny because to show all visual information in all directions at once in a rectangular image so something must be distorted. There is no distortion through the horizontal center of these image but as you move closer to the top (zenith) and bottom (nadir) there is more and more distortion until at the very top and bottom pixel is a line across the entire image. An equirectangular image is just like a Mercader projection of the earth that everyone is used to seeing.
