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Long Working Distance Objectives
Thorlabs offers Mitutoyo Plan Apochromat Objectives with 5X, 10X, 20X, or 100X magnification. These plan apochromat objectives feature chromatic correction at three wavelengths and spherical correction at two wavelengths to provide a flat field of view. The long working distance provides a wide space between the lens surface and the object. See the Objective Tutorial tab for more information about this objective type. Designed for a tube lens focal length of 200 mm, these objectives are ideal for machine vision applications or any application that requires a significant distance between the objective lens and the object. See the Specs tab for details on each of the objectives available here.
The objective housings are engraved with the magnification and the numerical aperture. The housings have external M26 x 0.706 threads. The objectives can be integrated into an SM1 lens tube system with the use of an SM1A27 adapter. These objectives do not feature adjustment to correct for cover glass thickness and should be used without a cover slip.
These Mitutoyo objectives have a parfocal length of 95 mm (see the Specs tab for complete specifications). To use these objectives alongside other manufacturer standards, such as Nikon objectives with a 60 mm parfocal length, we offer Parfocal Length Extenders. For instance, the PLE351 Extender can be used to increase the parfocal length of an Nikon objective from 60 mm to 95 mm.
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Note: This microscope objective serves only as an example. The format of the engraved specifications will vary between objectives and manufacturers.
Thorlabs offers plan apochromat objectives from Mitutoyo. This guide describes the features and benefits of these objectives.
Plan Apochromat Objectives
These objectives do not feature adjustment to correct for cover glass thickness and should be used without a cover slip.
Glossary of Terms
M = L / F .
The total magnification of the system is the magnification of the objective multiplied by the magnification of the eyepiece or camera tube. The specified magnification on the microscope objective housing is accurate as long as the objective is used with a compatible tube lens focal length.
Numerical Aperture (NA)
NA = ni × sinθa
where θa is the maximum 1/2 acceptance angle of the objective, and ni is the index of refraction of the immersion medium. This medium is typically air, but may also be water, oil, or other substances.
FN = Field of View Diameter × Magnification