MicrobeHunter.com Microscopy Forum

Very nice videos 75RR ! Both are detailed and interesting. Thanks.

Very fine details, really nice! You can clearly see the structure of the rod organ in Peranema. What other protozoans did you see in that sample?

Thanks mintakax and Wes

What other protozoans did you see in that sample?

Quite a varied lot. Surprised me, was not expecting much.

I suppose since it is the end of summer it is concentrated.

Here are a couple more from the sample:

Fantastic - thanks.

Very nice catches 75RR. How did you manage the oil immersion? There seems to be quite a thick liquid layer under the coverglas and this usually causes issues for such high n.a. objectives (low working distance) and oil immersion (movement or "pumping" of the coverglas due to re-focusing)? .

Many thanks PeteM and ImperatorRex

How did you manage the oil immersion? There seems to be quite a thick liquid layer under the coverglas and this usually causes issues for such high n.a. objectives (low working distance) and oil immersion (movement or "pumping" of the coverglas due to re-focusing)? .

In this case that was not a problem as there was some large detritus that kept the cover slip from moving down, the downside of course was that the image quality suffered as several of the smaller subjects were not pressed up against the glass - the equivalent of having a thicker cover slip than recommended, which with the 63x/1.4 is very noticeable.

Did you oil the top lens of the condenser?

Did you oil the top lens of the condenser?

Yes I did. In fact I always do. In for a penny in for a pound.

Thanks for the info 75RR.
I often use water instead of oil for the condensor front lense, just because of ease of cleaning. Works quite well till something like n.A. 1.2 or bit more.

Looking through the bertrand lens on the optovar unit I see an obvious difference upon oiling the condenser lens. Without oil I see a fairly limited field of illumination and following oiling the illuminated area increases dramatically. Now I wonder what difference there would be between using water, oil and other liquids with intermediate refractive index.

Wes wrote: ↑

Sat Sep 28, 2019 9:37 pm

Looking through the bertrand lens on the optovar unit I see an obvious difference upon oiling the condenser lens. Without oil I see a fairly limited field of illumination and following oiling the illuminated area increases dramatically. Now I wonder what difference there would be between using water, oil and other liquids with intermediate refractive index.

I would not recommend all of them but some might do at a pinch if you run out of immersion oil.

75RR wrote: ↑

Sat Sep 28, 2019 10:15 pm

Wes wrote: ↑

Sat Sep 28, 2019 9:37 pm

Looking through the bertrand lens on the optovar unit I see an obvious difference upon oiling the condenser lens. Without oil I see a fairly limited field of illumination and following oiling the illuminated area increases dramatically. Now I wonder what difference there would be between using water, oil and other liquids with intermediate refractive index.

I would not recommend all of them but some might do at a pinch if you run out of immersion oil.

Nice list! I was thinking about glycerol, its very easy to clean as its water soluble and its refractive index is pretty close to the desired value.