Stereo Microscopy

Abstract

Experiment 4.1: The Stereo Effect. Two examples of stereo pairs are presented in Figures A4.1 and A4.2. Figure A4.1 depicts the topography of crystals of native silver. The left-hand image is recorded at a nominal stage tilt of 0^° while the right-hand image is recorded at a stage tilt of 8^° for a difference in tilt angle of 8^°. Note that if the tilt angle is less than 5^° the stereo efect is reduced. Figure A4.2 shows the surface relief on a crystal of the mineral galena. The left-hand image is recorded at a nominal stage tilt of 0^° while the right-hand image is recorded at a stage tilt of 8^° for a difference in tilt angle of 8^°. (Note that the SEM used to prepare these images was configured such that the tilt axis was vertical on the recorded image with the E-T detector located on the upper right-hand side. The sense of illumination in these images thus appears to come from the upper right) At higher magnifications the surface relief is likely to be less. Thus, to obtain a stereo effect on a surface with only a small amount of topography, the tilt angle must be increased.