Quote Originally Posted by m1tch View Post
I will be creating an insert with some ground glass (probably tracing paper lol) recessed slightly to match the recess of the DDS, that way when I focus onto the ground glass it will be the same thing that the film 'sees' when I do the exposure.
The most accurate insert is an DDS itself, you can cut a hole through the septum and use a diffusing gel as a ground glass. A bit destructive, yes, but rather accurate and simple.