Bought another Sears lens on e-bay for $11.50; this time a 50mm f2.0. Here are the first pics with it of a weed called Coltsfoot.
1. Wide open @ f2.0
2. Wide open again with a 12mm extension tube.
3. f5.6 & 12mm extension tube.
I used a gorilla pod, 2 way focus rail & self timer.