Superresolution.
Another possibility which wouldn't require holding a sample close to the camera might be to use the method of superresolution. This increases the resolution by combining several images. The technique can improve the resolution by a factor of n^(1/2) by using n images:
THE SUPERRESOLVED SUPER PAN: IMPROVED RESOLUTION OF THE MARS PATHFINDER LANDING SITE USING SUPERRESOLUTION ON THE IMP SUPER PAN DATA SET.
http://www.lpi.usra.edu/meetings/lpsc2000/pdf/1753.pdf
Bob Clark