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Versión/Version 1; Jul 2017
Check there is dust on the precondenser's lens, upper lens of the condenser or the eyepiece,
as well as the cleanliness of the sample. Once you find out where the dirt is you should clean it
as explained before.
If the sample gets fuzzy while observing:
Check the tension adjusting ring, as it may be too weak and provoke an involuntary fall of the
stage.
If an area in the field of vision is out of focus:
Check the objective is properly located on the luminous beam's path. If not you should turn it
until it is appropriate position.
Check the sample is properly located on the stage, making sure it is held by the stage clips.
Then, if it does not focus you should revise the pre-focusing control.
If the frontal lens of the objective touches the prepared slide when focusing:
Check the prepared slide is not the other way round (being the cover glass over the slide) and
place it properly in case it is appropriate to do so. Check also the slide's thickness, which has to
have a standard thickness of 0,17 mm.
8.
Recommendations
When using the oil immersion objective you should notice the following:
a) In order to use all the numerical aperture of the oil immerson objective:
- Pre-focusing: Focus the sample with the objective with less magnification (4x).
- Put a drop of oil immersion on the cover glass.
- Rotate the nosepiece, place the immersion objective and arrange the focusing with the fine
adjustment knob.
b) You should avoid air bubbles in the oil so as not to spoil the resulting image. To do so you
should move the pre-focusing control up and down to make the oil layer uniform.
c) Turn the nosepiece and then locate the oil immersion objective; you can adjust focusing
with the fine knob.
