Choosing a (digital?) microscope for a hobbyist

December 3, 2009 8:37 AM

Please help me buy a high-power microscope for a hobbyist. Requirements inside.

I'm buying a microscope (as a Christmas gift) for my wife. She would like to use it for visualizing molds, tiny animals, cells (see below), tiny plant parts, and so on (the sort of stuff one looks at in biology courses, I think). She's not all that clear on what exactly she wants to do with it.

After a few sessions of browsing Google and Amazon, I realize I simply don't know enough about microscopy to make a good decision here. I'm thinking of pairing this camera accessory with a decent microscope. But which microscope might be good?

Another possibility is this one, an econo-model made by Celestron that has a digital LCD screen instead of an eyepiece. But why is it so cheap? I'm concerned about the low price, as really good (i.e., medical- or lab-grade) microscopes seem to be extremely expensive.

2) Higher-powered objectives/lenses (like 100x, 400x) seem to require the use of special oil on the slides. This seems like a big hassle for a casual hobbyist; is it?

3) What are the smallest kinds of things she would be able to see with the above? (most important question!) Would she be really disappointed not to have higher-powered oil objectives available? Can you actually "see cells" (and in what way?) at 400x?

Really confused by the options; please hope me.

posted by Maximian to science & nature (7 answers total)

Higher-powered objectives/lenses (like 100x, 400x) seem to require the use of special oil on the slides. This seems like a big hassle for a casual hobbyist; is it?

No--very easy.
posted by flug at 8:55 AM on December 3, 2009

When we were looking for something similar I found this site quite helpful: http://www.microscope-depot.com/

FWIW we ended up getting something like this: http://www.microscope-depot.com/seriesP.asp

That was for a nine-year-old home schooler and we have been *very* pleased with it.

The things this one had, that the cheaper models didn't, that we considered quite important and definitely turned out to be very useful:

* Fine focus. This is a must. Cheaper models only have the course focus.

* Mechanical stage. This allows you to move the thing you're looking at precisely. Without the mechanical stage looking at something even at 100X is an exercise in frustration because the gentlest nudge from your finger just makes the thing whiz across the viewing field.

* Abbe Illumination. This has an adjustable lens and an adjustable iris to control the light source. Making these changes can dramatically affect the way things look--for instance, increasing the contrast to make fine structure pop out. By adjusting the light source you can quite literally make invisible things become visible.

If the price tag is too high on that model, you might look at this one (though I would definitely choose the option for mechanical stage):

http://www.microscope-depot.com/seriesO.asp

You're saving about $100 there and giving up the 1000X magnification and the Abbe Illumination.
posted by flug at 9:20 AM on December 3, 2009

Higher-powered objectives/lenses (like 100x, 400x) seem to require the use of special oil on the slides. This seems like a big hassle for a casual hobbyist; is it?

Also I would add that the oil is really only generally used on 1000X (one THOUSAND times) magnification and higher.

The magnification is a bit confusing because the number listed for the objective has to be combined with the magnification of the eyepiece. For instance in the Model O I mentioned above, the specs mention "Three DIN objectives: 4X, 10X, 40XR". Because the eyepiece of Model O is a 10X, the resulting magnification is 40X, 100X, and 400X.

None of these is an oil immersion lens--those are always specially made & specially labelled.
posted by flug at 9:30 AM on December 3, 2009

Professional microscopist here; feel free to memail me with questions.

if you're going to be using the microscope much for looking through the eyepieces rather than using a camera, I would advise getting a binocular microscope. It's much more comfortable to look with both eyes than just one. The earlier recommendations for fine focus, mechanical stage, and Abbe (I would call it Kohler) illumination are all right on.

Many cells are fairly large and can easily be seen at 10 or 20x (= 100 or 200x when combined with the eyepiece magnification). One easy to get sample is your own cheek cells, which can be easily seen at this magnification - use a toothpick to scrape the inside of your cheek and smear what you get onto a slide. Put a coverslip on it and take a look. Unfortunately, like a lot of cells they are fairly transparent and so are only really impressive with phase contrast or other contrasting techniques. With a 40x objective you can even see quite small cells like yeast (only about 5-6 um in diameter), although again, contrast can be a problem. If you have an adjustable aperture diaphragm (it seems that these scopes don't) you can close that down which will increase contrast. The 100x oil immersion lens is probably only really necessary if you want to see bacteria or look at subcellular components. You should also be able to add a 100x objective later if you want.

Oil immersion is pretty simple. Just make sure you don't get oil on the non-oil objectives, and wipe off the excess oil with lens paper when you're done. You may periodically need to clean the old oil off the lens with lens cleaner, but you shouldn't have to do this too often.

One thing that might also be nice would be to get a set of prepared slides from Carolina Biological or similar - these will be stained so they are much easier to see with regular microscope optics (i.e. no phase contrast).

Finally, there is a lot of good information about microscopy on the web. My favorite site is microscopyu.com. It's aimed more at the scientific community but if you look through there you should find lots of information about the basics of microscopy.
posted by pombe at 10:19 AM on December 3, 2009 [1 favorite]

Consider buying from a company liquidation rather than new. (A lot of that stuff ends up on ebay too). Liquidated lab equipment is generally used-but-durable pro-level gear sold for pennies on the dollar.
posted by -harlequin- at 12:09 PM on December 3, 2009

PZ Meyers' holiday microscope shopping guide
posted by ShooBoo at 12:13 PM on December 3, 2009

If you do this, go to a local pond or something a little before Christmas and get her a jar of pond water (with some algae and maybe a dead leaf in there). A big magnifying glass can make pond water interesting.

Here are some images of things at 40 to 400x to give you an idea.
posted by Kid Charlemagne at 10:30 PM on December 3, 2009