Does anyone have any books or websites to recommend on the topic of lens design? Primitive Photography has a few suggestions based on classic lens design, but I am looking from something more comprehensive. Sidney Ray's Applied Photographic Optics is great, but it's very dense and due back to the library before I will have time to absorb all of it. Ideally, I'm looking for something with conscise information about calculating focal length, covering power, deplth of focus, etc. This trial-and-error approach is really getting tiresome.