vik, Yep, I can do a lot better. The radius on that point is a smooth 2 microns (big blob in the lower right is the hypodermic tip). The smoothness is beyond my current optics, but shows no significant deviation at 0.25 microns/pixel. Woohoo!
Ultrafine wire point vs. end of a hypodermic needle. A sequence of zooms. 1 micron per pixel.
Ultrafine wire point vs. end of a hypodermic needle. A sequence of zooms. 250 nanometres per pixel.