Reflection-back-through-the-fiber scanning near-field optical microscopy (SNOM) measurements with uncoated tapered fiber tips, that remain cold, were performed under shear-force distance control for opaque and transparent rough samples. The feedback dynamics of the commercial (DME) RASTERSCOPE SNOM were tested with a 3000/500 nm gold grating at very high scan rates. Slow rates give rise to thermal broadening due to heating of the gold surface by partial light absorption. Enhancement of the light intensity at the base by reflection from steep walls on four sides is reported, the steepness contrast being less important. Doped gallium arsenide substrates give materials contrast. Extremely rough porous silicon has been probed. Organic chemical contrast is seen for the first time with SNOM on partly oxidized anthracene at large dislocations. Anthracene, anthraquinone, and their charge-transfer complex are clearly discriminated by different reflectivities. Irradiated alpha-cinnamic acid exhibits a chemically uniform surface and, thus, no SNOM contrast despite the anisotropic mu m high features that are observed. Photolithography on light-absorbing 2,5-dibenzylidene-cyclopentanone crystals with the tip illuminated at an approximate to 10 nm distance provides an easy, inexpensive, and rapid performance test of single tips. Very long local irradiation creates features that widen and reach heights of 300 nm.