About This Blog

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.

A more realistic view of these images can be seen through the use of web viewer software that is invoked when you click on one of the thumbnails. The web viewer reads the equirectanglar image and removes the distortion and shows a more realistic image in a rectangular area of your web browser. As you drag the cursor across the image displayed by the viewer you can control which direction you see. Web viewers give you the feeling that you are suspended on the inside of a photo sphere.

There are several kinds of web viewers. The viewers I use on this blog are QuickTime, Java and Flash. Each type of viewer has it's own benefits. To view images with a viewer you must have the viewing software installed on you machine. QuickTime is high quality but installed on only about 50% of PCs and 100% of Macs. Java is more widely installed on both PCs and Macs but the quality of image it displays is not quite as good as Quicktime. Flash is installed on 90% of PCs and Macs but the quality is not as high as Java and QuickTime. Flash viewers appear to be jerky when the image is moving but are high quality when the image is stopped.