Microscopy Primer
Light and Color
Microscope Basics
Special Techniques
Digital Imaging
Confocal Microscopy
Live-Cell Imaging
Photomicrography
Microscopy Museum
Virtual Microscopy
Fluorescence
Web Resources
License Info
Image Use
Custom Photos
Partners
Site Info
Contact Us
Publications
Home

The Galleries:

Photo Gallery
Silicon Zoo
Pharmaceuticals
Chip Shots
Phytochemicals
DNA Gallery
Microscapes
Vitamins
Amino Acids
Birthstones
Religion Collection
Pesticides
BeerShots
Cocktail Collection
Screen Savers
Win Wallpaper
Mac Wallpaper
Movie Gallery

Köhler Illumination: Interactive Tutorials

Eyepiece Diopter Adjustment

A majority of modern research-grade optical microscopes have binocular or trinocular observation tube systems. The eye tubes are usually adjustable for a range of interocular distances to accommodate the interpupillary separation of the microscopist (usually between 55 and 75 millimeters).

This tutorial examines how the eyepieces are adjusted for the microscopist's optimum interpupillary distance and how the diopter adjustment on each eyepiece can be made independently. To operate the tutorial, use the Interpupillary Distance slider to adjust this value (the size, in millimeters, is given just below the slider). Once the proper interpupillary distance has been set, use the Microscope Focus slider to bring the sample very close to focus while observing the image formed in the left eyepiece. When the specimen approaches focus, utilize the Left Eyepiece Diopter slider to bring the sample into sharp focus. Next, use the Right Eyepiece Diopter slider to bring this eyepiece into focus, matching the left eyepiece.

Many polarized light microscopes are equipped with an eyepiece diopter adjustment, which should be made to each of the eyepieces individually. Some microscopes have a graded scale on each eyepiece that indicates the position of the eye lens with respect to main body of the eyepiece. Other models hold the body of the eyepiece in a fixed position securely in the eye tube with a pin and slot. The first step in diopter adjustment is to either line up the graded markings (Figure 10) on eyepieces equipped with such markings or turn the eye lenses clockwise to the shortest focal length position. Next, focus the specimen with the 10x objective and then rotate the nosepiece until a lower magnification objective (usually the 5x) is above the specimen. At this point, refocus each eye lens individually (do not use the microscope coarse or fine focus mechanisms) until the specimen is in sharp focus. Rotate the 20x objective into the optical path and refocus the microscope with the fine focus knob. Repeat the diopter eye lens adjustments with the 5x objective (again not disturbing the microscope fine focus mechanism), and the microscope should be adjusted to the correct diopter settings. These settings will vary from user to user, so record the position of the eye lenses if the eyepiece has a graded scale for quick return to the proper adjustment.

Contributing Authors

Mortimer Abramowitz - Olympus America, Inc., Two Corporate Center Drive., Melville, New York, 11747.

Matthew J. Parry-Hill and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.


BACK TO ANATOMY OF THE MICROSCOPE

Questions or comments? Send us an email.
© 1998-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Monday, Sep 10, 2018 at 09:21 AM
Access Count Since May 06, 1999: 43544
For more information on microscope manufacturers,
use the buttons below to navigate to their websites: