I just bought a set from Schneider through that filter sale that Century Optics is doing. This isn't something I would normally buy, because honestly, how often are you going to want to pull off a gimmicky shot like this? But hey, for $50 bucks each -- why not? There's no documentation, naturally, and I can't seem to make a useable shot. Can anyone direct me to a book or something that explains how to take advantage of these things? I'm trying to use them with a Century anamorphic adapter, which Century's Web sits claims is commonly done. I gather that you have to carefully plan the distance to the lens for the background and the foreground. For anyone who has used these before: where do you start? Do you focus to the background and then manipulate the foreground to make it work? I'm assuming the half with the glass should capture the foreground, but I'm just guessing.

Not me. But I do recall we had a DOF thread in which Charles Papert touched on the subject (http://www.dvinfo.net/conf/showthread.php?s=&threadid=2452&perpage=15&highlight=split%20diopter&pagenumber=2) long ago.