Lab Recipes
How to Use the Stereo Zoom Microscopes
Dan Anderson
This document refers to the Zeiss SV8 and Olympus SZH stereo microscopes (Note 1). Operationally, they differ in how the eyepieces are focussed. The beginning of this document is stated as recipes, the details section that follows is referred to with note numbers.
HOW TO FOCUS THE EYEPIECES The eyepieces have their own focus mechanisms to adjust them to your eyes (Note 2). The strategy is to first adjust the eyepieces without focussing on a sample, then to focus on the crystal (etc.) without further adjusting the eyepieces. The focus for the thing to be examined is adjusted with the focus knob (see below), not the eyepieces.
It is best to start with the lamp on, but nothing on the stage. If you usually wear glasses, then wear them to focus the eyepieces. Relax your eyes so that they focus very far away. Without re-focusing your eyes, look through one eyepiece that contains a reticle. Rotate the eyepiece until the reticle comes into focus. For the Zeiss microscope with a camera, repeat the process for the other reticle.
For the microscopes with only one reticle, focus the reticle eyepiece as above, then place a razor blade on the microscope stage. Make sure that the aperture is all the way open (Note 3); turn the dial (Zeiss) or move the slider (Olympus) on the front of the microscope to the maximum open position. Looking only through the reticle eyepiece, iteratively move the sharp edge into the center of the field of view, focus on the sharp edge using the focus knob (see below), and increase the magnification to its maximum by rotating the magnification knob (see below). Without touching the focus knob, rotate the other eyepiece to focus on the sharp edge. When doing this for the Zeiss SV8 microscopes that we have, keep the blade straight from front to back (Note 4).
HOW TO FOCUS First, focus the eyepieces to your eyes, as described above. Then focus on the crystal (etc.) with the focus knob. The focus knobs are the ones without numbers that stick out the sides of the microscopes (Note 5). It's in focus when it has sharp edges (Note 6).
HOW TO CHANGE THE MAGNIFICATION The magnification knobs are the ones with numbers on them that stick out the sides of the microscopes (Note 7). Rotate towards larger numbers to make the image larger, towards smaller numbers to make it smaller (Note 8).
CLEANLINESS The optical surfaces of the microscope may be cleaned with lens paper (Note 9) wrapped around a cotton applicator, then dampened with the ammonia version of Windex (Note 10). Wipe with a gentle circular motion. Do not rub with any force. DO NOT USE KIMWIPES ON OPTICAL SURFACES (Note 11). The optical surfaces may be wiped dry with lens paper.
NOTE 3 Microscope resolution works the same as x-ray diffraction resolution. High angle scatter (aperture open all the way) results in high resolution. The resolution limit in practice is limited by our requirement that we can fit our hands between the stage and the objective lens; the maximum scatter angle isn't much in these microscopes. See also Note 6.
NOTE 4 Our Zeiss SV8 microscopes are equipped with dual objectives. The focal planes are tilted. Simultaneous focus for both eyes can be achieved only along the line of intersection between those two tilted focal planes. Therefore, the razor blade has to go through the center of the fields of view, oriented straight from front to back. See also Note 6.
