 |
Köhler Illumination: Interactive Tutorials
Condenser Aperture Diaphragm
Control Of Specimen Contrast
The aperture diaphragm acts essentially as a control for resolution and contrast in optical microscopy. By varying the size of the diaphragm opening, the illumination cone projected into the objective is changed.
To see how this affects specimen images, use the slider to open and close the condenser aperture diaphragm. Opening the diaphragm too much results in glare and loss of contrast, while closing it too far results in increased diffraction and loss of resolution. An intermediate position is optimum, which corresponds to an opening size of between 60 and 90 percent. The condenser diaphragm image seen beneath the photomicrograph indicates how the image of the condenser diaphragm appears at the back focal plane of the objective.
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 12:29 PM
Access Count Since August 12, 1998: 71767
For more information on microscope manufacturers,
use the buttons below to navigate to their websites:
