Here's a breakdown:
* Objective Lens: The lens closest to the specimen that magnifies the image.
* Front Lens Element: The outermost lens of the objective lens.
* Specimen: The object being viewed under the microscope.
Importance of Working Distance:
* Space for Manipulation: Working distance provides space to manipulate the specimen, particularly for delicate samples or when using micro-tools.
* Depth of Field: A longer working distance typically results in a larger depth of field, meaning more of the specimen is in focus at once.
* Objective Choice: The choice of objective lens often depends on the desired working distance. Higher magnification objectives generally have shorter working distances.
* Immersion Objectives: Objectives designed for oil or water immersion have very short working distances, as the immersion medium fills the gap between the lens and the specimen.
Factors Affecting Working Distance:
* Magnification: Higher magnification objectives usually have shorter working distances.
* Objective Design: Different objective lens designs can influence working distance.
* Immersion Medium: Oil or water immersion objectives have shorter working distances than dry objectives.
In Summary:
Working distance is a crucial parameter in microscopy, determining the space available for specimen manipulation and affecting depth of field. It is essential to consider working distance when choosing an objective lens and preparing specimens for observation.