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Using 100x oil phase objective after using the 50x oil darkfield.
Here you would simply rotate the 50x out of position and rotate the 100x oil phase objective
into place (moving it back and forth about a millimeter either way to well set the lens into the
oil.) It is conceivable that you might need another drop of oil on your slide cover depending
on how much you may have moved the slide around using the 50x. If that is the case, just
rotate the 100x out of place and put another drop of oil down. Set the condenser to PH3 and
you will have a 100x phase contrast view that is much magnified.
Using 100x oil phase objective after using the 40x oil non-oil objective.
Using 100x oil phase objective after using the 50x oil darkfield.
This process is similar as to using the 50x oil objective.
We will assume that you have a live blood slide specimen
on your microscope stage and you have been viewing
this with the 40x non-oil objective in phase contrast (PH2)
or darkfield (DF) mode. Rotate the 40x objective out of
the way so you are looking at your sample as shown in
the picture. You will place a drop or two of the
microscope objective immersion oil directly onto the top
cover slip where the 100x oil phase objective will be
rotated into place. After dropping on the oil, you will rotate
your oil objective into place and move it back and forth in the oil a few times (a millimeter either
way) to well seat the oil around the objective lens. Your turret condenser should be if PH3 mode.
Oil
Oiling the Condenser
The microscope’s universal turret condenser has a numerical aperture of 1.25NA so it can be
oiled. Numerical aperture provides resolving power when magnifying a specimen. With objectives
up to .9 NA you do not need oil on the condenser. When using objectives that go beyond .9NA,
oiling the condenser might bring a bit more resolution. Many people that use oil on the top of the
slide for the objective, often do not use oil on the condenser. More or less this is due to the hassle
factor. When moving back and forth between slides, especially when going from live blood
imaging to dry layer and back to live blood, having to clean the condenser each time the slides
change is a big hindrance. You might find yourself that you choose not to oil the condenser when
using oil objectives.
For reference, the 50x oil objective has a numerical aperture of .9NA, the 100x phase is 1.25NA.
If you want to oil the condenser, you need to have your specimen off the stage and out of the way
of the top lens of the condenser so you can add your oil, then place the slide on top of the oil
centering your sample over the oil.
Note that for clean up
, the condenser lens can be pulled
forward making clean up easier. When using oil, you must ALWAYS clean your objectives and
condenser at the end of the day, sometimes the condenser during the day so as not to let the oil
build up and spill over the retaining edge that surrounds the condenser top lens.
See the
Olympus manual for more details on use of immersion oil and clean up.
Never go back to the 40x non-oil objective after using an oil objective as it is not designed
for oil and if oil seeps into the lens chamber it can be ruined.
