October 15, 2019

Biological Microscopes

This page is largely a place where I am collecting notes and information that help me to understand and use various biological microscopes that have come my way. Microscopy is a large and interesting subject, with many aspects. Optics and equipment are one, and what I focus on here. Microscopic life is something else entirely and I neither know much about it or attempt to address it.

Someone said that a microscope is more a "resolving device" than a magnifying device. It enables you to see structures you could not otherwise see. People love a single number to rate things, but this approach is almost always misleading. A good guideline is that any claimed magnification above 1000x is bogus. (Most quality microscopes have a 100x oil objective and a 10x eyepiece). Resolving detail is what it is all about.

My microscopes

I am ignoring my stereo microscopes entirely here. I use them all of the time for looking at minerals (micromounts) and they deserve a section of their own. And they will get one someday. For now, the following list is (mostly) just my biological microscopes.

Pond life and microorganisms

At some point, just like identifying the birds you see, you ought to be able to learn to identify protozoans. There must be keys and books?

Using a microscope

You would think there is not all that much to this, but ... Note that "Micrographia" is a fairly famous book (from 1665) by Robert Hooke. It looks like it is available free as a Kindle edition.

Tube length

For a long time, 160mm was standard, then 170mm began to be used more often. If you have a microscope with a tube length of 170mm, you can use both 170 and 160mm objectives. A 160mm tube length microscope will not properly use 170mm objectives.

An even more modern trend is "infinite conjugate" objectives -- here the tube length (behind the objective) can vary -- but a relay lens must be present inside the microscope body, so such objectives can only be used on microscopes with the appropriate relay lens.

Microscope illuminators

The worst thing of all is a mirror that you tilt to try to reflect light up through whatever you are looking at. Thankfully none of my microscopes offer this arrangement. They do have incandescent light sources, most of which are either broken or have the bulbs burned out. Using an LED is a better option for many reasons.

This and that

Have any comments? Questions? Drop me a line!

Tom's microscope pages / tom@mmto.org