In article <46uqma$28ge@bird3.i-link.net>, soteric@i-link.net says...
(...)
> Regardless, at any aperture on any lens the edges won't be as sharp
>as the center (assuming you're focusing on the center).

This reminds me that I rarely focus in the center - since a 35mm
negative is rarely flat in a glassless carrier (and I will not deal
with the dust problems of a glass carrier), it is useful to find a
compromise place in the negative to focus (ROUGHLY mid way from center to corner) to more nearly average out the focus error range, and stop down to f8 or so to try to cover the errors with DOF.
Hope this helps.