Posted by
Steffen Dietzel on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Oil-vs-water-objectives-tp7579114p7579130.html
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On 04.10.2012 18:20, Cammer, Michael wrote:
> Also, while people have generated various test samples of
collagen and latex and acrylic and fat globules and glass
beads and carrageen gum and dissolved Scotch tape glue etc.,
the only test sample that really answers the question is the
sample itself.
Again, I agree, in particular if you look at tissues with more or less
unpredictable optical properties. Still, bead preparations allow to
demonstrate the general effect very clearly and thus convincingly. They
also allow quantification and sometimes hard numbers help to convince
people. Some person might argue that they don't care about resolution
since s/he is planning to use a 1 µm pixel size anyway. But you still
can convince these people if you can show them that they will also loose
a lot of intensity.
I use such a demonstration to argue for the usage of 170 µm coverslips
and a good embedding medium.
On 05.10.2012 02:40, Guy Cox wrote:
> Nobody seems to have mentioned so far that the NA of an oil
objective will NOT be 1.4 if it is imaging a sample in water.
The maximum it can be is 1.33 - the refractive index of water.
...
> So the oil objective has little or no advantage in NA
Is that really true? If there is oil between the coverslip and the oil
objective, but water immersion for the water objective, this should make
a noticeable difference in effective acceptance angle, should it not?
(Assuming the object is rather close to the coverslip).
Steffen
--
------------------------------------------------------------
Steffen Dietzel, PD Dr. rer. nat
Ludwig-Maximilians-Universität München
Walter-Brendel-Zentrum für experimentelle Medizin (WBex)
Head of light microscopy
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