Parfocality means that when one ocular lens pathway is in focus, the other ocular lens pathway will also be in focus. In order to perform this, pay attention to the diopter settings on each ocular. Plus, know your own eyeglass prescription. In addition, if the diopters are not set properly, you could be “in focus”, but your assistant using the side observer and/or the monitor image will be out of focus.


parfocality adjustments image

Personal Parfocal adjustment:

Follow these instructions in order to obtain your own personal parfocal settings:

A. Position the microscope above a flat, stationary surface.

B. Make a dot on a piece of white paper with a pen or pencil to serve as a focus target and place it within the illumination field of the microscope.

C. Set both ocular diopter settings to “0”. Then, adjust the inter-pupillary distance so that “one” image is viewed.

D. Set the microscope to its highest magnification setting and focus the microscope until a sharp image is obtained. 

E. Change the magnification setting to its lowest position. Then, one at a time, look through the left and right oculars. Then, turn the diopter ring on each ocular until the image is clear and sharp. Tighten the diopter lock button and record the settings for future use.

F. Whenever that operator uses the microscope, they can dial in their diopter settings.

The operator does not have to repeat the same procedure each time the microscope is used. However, due to changes in eye correction over time, it is recommended the operator repeat this procedure once or twice per year.

Chuck Luley