Motic BA210E, Instruction Manual

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4.6 Diopter adjustment
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Diopter adjustment compensates for the differences in vision between the left and right eyes. In
addition to making observation through both eyes easier, this adjustment also reduces the extent to
which focusing is lost when the objective magnification is changed. In particular, this occurs when a
low magnification objective is used.

The left eyepiece has a separate focusing provision to compensate for slight differences in the
focusing of each eye.

Using the right eye only and viewing through the right-hand eyepiece, adjust the focus with the
microscope fine or coarse adjustment until the image of the specimen is at its sharpest.

Using the left eye only and viewing through the left-hand eyepiece with its independent diopter-
focusing ring, focus until the specimen image is at its sharpest.

The microscope should now be ready binocular viewing.
4.7 Condenser (sourced focused (critical) illumination)


Critical illumination relies on using the sub-stage condenser to produce a focused image of the
homogeneous light source in the plane of the specimen in order to achieve an even illumination
condition over the entire field of view.

To have the light source focused in the plane of the specimen, an imaging disc with concentric
circles (and with its matte surface facing toward the microscope base) is placed on the field lens
and is focused on to the specimen plane. This is achieved by moving the condenser up or down
with condenser focus knob.

The correct vertical setting of the condenser remains unaltered when changing magnifications.
Because the light source is imaged onto the specimen, both the specimen and the light source are
said to be in the field plane. The condenser iris diaphragm controls the N.A. of the system, and is
therefore said to be located in an aperture plane of the microscope.