Extension tubes - new technical article

While responding this morning to an inquiry from another member about extension tubes, I found that a technical article on the subject, done late in 2007, had never been completed and released (doubtless overtaken by events - this was about the time we moved from East Dallas to Weatherford, a gigantic deal).

In any case, the piece is now done and up on the Pumpkin. Entitled "The Mathematics of Extension Tubes in Photography", it is available here:

http://dougkerr.net/pumpkin/index.htm#ExtTubes

Best regards,

Doug