John Carmichael wrote :<snip> But I discovered that by using digital editing, you can stretch or compress a photo so that it appears that camera was directly over the dial! I discovered this while using the "perspective" and "distort" features of Adobe Photo Delux. <snip>
Yes, it works quite well to a certain extent; but not altogether. Imagine a vertical direct East or West dial, with the gnomon parallel to but standing away from the surface. The proper "face on" view will show only the edge view of the gnomon. However your view from somewhere in front and underneath will show you the bottom surface of the gnomon as well. This will not disappear by the stretching in Adobe - nor, if it is a solid gnomon, will the part of the dial surface hidden behind (above) it come into view on your computer screen! So beware of that; I try to stand a long way back from high vertical dials and use a long focus lens. I don't agree with the idea that one should stand at essentially the same distance away from the wall as the vertical dial is up the wall, which makes the height of the dial submit the greatest angle to the viewer looking up at 45 degrees. That gives a massive 0.7 : 1 linear distortion (which as you say can be restored digitally) - but the gnomon's odd shape cannot. Horizontal dials on a high plinth aren't so easy, though ... Andrew James
