I have put two articles on aspects of depth of field for tilted standards on my web page at

www.math.northwestern.edu/~len/photos/

The first article, entitled` View Camera Geometry,' is a highly technical article on the geometry of the subject. It uses concepts from projective geometry, some calculus, and lots of trigonometry. It requires a fairly good background in the relevant mathematics, so I don't recommend it for general readers, even for those with a strong background in technical areas. I wanted to get it all straight in my mind, whatever it took to do so, and I think I've accomplished that. In the process I was able to solve some of the problems arising when one tries to analyze these matters.. The article is complete, except for correcting typos and minor revision of language which will continue..

The second article, entitled `Depth of Field for the Tilted Lens', is still a work in progress. It is an attempt to describe some of the results of the first article without a lot of equations. (There may be a few, but they won't be essential to understanding the discussion.) It should be understandable to a much larger audience. Bu t it does assume some familiarity with technical concepts in view camera photography, such as the Scheimpflug and Hinge Rules, circles of confusion, the wedge shape of the DOF region for tilted lens plane, and similar concepts. I made some effort to explain all that, but it would be a lot to absorb for someone not already familiar with the ideas. The major aim of the article is to show why in most circumstances, you can ignore the effect of tilting on the shape of the circle of confusion, and to indicate under what circumstances the effect might be large enough to matter. In the process, other interesting issues come up.

I welcome comments about either article, but I would be very surprised if I got many about the first article. The second article is another matter, and I hope to get many useful suggestions about how I should proceed.

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