GS wrote:
or should I spring for one of the lenses made specifically for the
digital?

Only if you want to save weight. Those lenses specifically made for DSLRs
have a smaller picture suited only for the smaller sensor but not for the
larger film. Therefore they can be made smaller, lighter and cheaper.
But on the other hand of course designers are pushing the limits within
those smaller boundaries now just as they did with lenses for film cameras.
That means when using lenses which were designed for film cameras a DSLR
with its smaller sensor would pick up only the center of the picture and
ignore the weak edges and corners.
Now with the redesigned smaller picture for DSLRs the weak edges and corners
are back within the borders of the sensor.

jue