A few years ago I began to wonder why there were no photographs that looked like the impressive wide-angle cityscapes painted in 18th Century Italy. You can see those on every postcard rack in Rome and Venice, beside modern photographic views—and the photos look narrow and drab by comparison. Surely, I thought, photographers could do better than that. I’ve learned how to make photographs that can at least stand up to comparison with 18th Century view paintings, and I know why there were no such photos before. It is because you can’t take pictures like that with a lens.
This article is a brief introduction to digital panoramic photography (DPP), a technology that literally separates an image from the lens that took it, then “re-photographs” it with a lens made of software instead of glass. I’ll demonstrate that magic with the software lens I designed to simulate the wide perspectives of 18th Century views, the Panini projection.
DPP programs are called stitchers, because one of their jobs is to merge separate photos. However, stitching is not important for our present purpose.
The technique described here applies equally well to single photographs, taken with wide, ultra-wide or fish-eye lenses, as do panoramas made from multiple photos. The real problem is how to make a flat image covering a very wide field of view look believable. The goal is to convince the viewer that your picture looks like the real thing, or better still, that the real thing looks like your picture. Many view paintings are geometrically inaccu- rate, but all make you believe “yes, that must be how it really looks.”
By wide field of view I refer to anything over 75 degrees, about the horizontal field of a 28mm lens on a 35mm camera. At that width, in a normal (rectilinear) image, the stretching at the edges called perspective distortion begins to disturb some people. It increases very rapidly as the field gets wider, so ultra-wide normal lenses, that cover 110 to 125 degrees make badly distorted images, that really need some adjustment. The need to “fix the perspective” is even more obvious with fisheye lenses and stitched panoramas. The Panini projection handles them all. It works well up to 150 degrees wide for most subjects, and even beyond 180 degrees in some cases.
My professional wide-angle perspective tool, Panini-Pro is scheduled for release this fall. But for these examples I used Hugin, a free, open source DPP software suite for Windows, Linux and Mac OS. Hugin offers many fixed and several adjustable “software lenses” called projections in DPP- speak. It has an interactive preview window where you set up views to be rendered (stitched) to high-resolution image files. Hugin gives top quality results, but is challenging to learn.
