Playing with the Lomo microscope using different condensers.
by Bill Resch


I love the aplanatic condenser which came with my Lomo microscope. Unfortunately it is not corrected for chromatic aberration. I always felt that this microscope could do a lot better with a better condenser. My Lomo, which has apochromatic objectives has excellent resolution, but some details are hard to see because it lacks contrast. Being able to shift the iris helps, but I thought that I should be able to see some detail without having to resort to it. The detail I am referring to, are the hole pattern on my favorite test object: Pleurosigma angulatum.

On my incessant internet searches, I noticed that some Meiji microscopes have an achromatic condenser. These condensers fit the Lomo perfectly. I bought one, but the test pictures I took were not convincing that I needed to have one of these.

Lomo condenser. 20X Apo objective. Lomo Koehler illuminator with improved bulb. (I got to like this illuminator. Its easy to set up.)

Meiji achromatic condenser.

The difference is so little that I could not make a judgment visually, because it takes time to exchange the condensers and I could not remember what I saw before. Looking at the pictures should make it easier to compare, but small variations in focus and Koehler adjustment could account for the difference. I just had to know...

Below: images of the iris edge focused as required for Koehler. Here is where the difference becomes apparent.


Two more images taken with a Lomo 40X achromat. Lomo condenser on left, Meiji on right:


My conclusion: If you have the aplanatic Lomo condenser, its probably all you ever need.

Darkfield condenser.

There is another thing I wondered about: how would the Lomo perform with a real darkfield condenser. I ordered a new one on eBay from one of those large microscope discount providers. It was $70.-, worth the try, N.A. 0.7-0.9. Should be fun. Actually it was. There are so many aspects to this hobby and sometimes the money spend turns out to be well worth it. Here are my unprofessional pictures I took with this dark field condenser: (images were much more striking visually)


40 X Lomo achromat. How is that for contrast?


20X Lomo Apo. (Under brightfield, I have a hard time seeing any detail with this 20 power objective.)

Comments to the author, Bill Resch, are welcomed

 

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Published in the September 2012 edition of Micscape Magazine.

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