This image was shot both with in D70 camera sharpening turned ON (set to Normal) and turned OFF. When the two images were "subtracted" from one another the next two images (#2 of 5 and #3 of 5) resulted and shows the differences between the two.
#2 & #3 are two different techniques for examining images for differences. Both were made in Picture Window Pro (PWP). #2 resulted from using PWP's Composite Transform with the compositing operation set to Subtract. #3 used PWP's Special Effects transform with the effect set to Difference and the option set to Offset Difference >> and this output was run through Levels & Curves Set Full Range option to enhance the contrast/tonal differences.
The technique to create #3 was suggested by Jonathan Sachs who is the developer of PWP (and developed Lotus 123 in another life) - thanks, Jonathan. If you've never tried PWP you're doing yourself a disservice.