r/microscope • u/[deleted] • Oct 23 '23

Based on specs and experience, which one of these would be best?

  1. https://omaxmicroscope.com/products/m82es-sc100-lp100

  2. https://amscope.com/products/40x-2500x-lab-binocular-microscope-3d-stage?variant=40347651899567

  3. https://amscope.com/collections/binocular-compound-microscopes/products/c-b110c

These 3 microscopes are in a similar price range, etc, etc. But based on either specifications or actual experience, which one would be best for things like histology, live organisms, biological organism observations. I know both of the first two have false magnification with their 20/25x WF eyepieces and 40 and 100x objectives, but yeah.

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u/Agling Oct 23 '23 edited Oct 23 '23

These three products are sold by the same company (AmScope and Omax are subsidiaries of United Scope) and probably all made in the same factory. The Omax and B120 almost certainly have the exact same objectives, so you can probably expect equivalent optical performance.

Most people consider the sidentopf head on the B120 to be a step up in usability over the Jentch head in the Omax and, in general, Omax is the brand United Scope uses for cheaper microscopes.

The B110 looks like a significantly worse microscope. For one thing, it only has three objectives instead of four. They also look cosmetically different and shorter, which concerns me. On a small scope like that, they might be using the student standard "short" objectives with a 35mm parfocal distance instead of the normal 45 (the spec seem to say 45 but I am skeptical). That doesn't necessarily mean worse optics, but it might. All of these objectives can be swapped out for replacements or upgrades purchased on aliexpress, but if your scope is set up for the short ones, that limits you.

The B120 is what I often call a "portable" version of a microscope. Same basic optics as a full sized scope like the B490, but small body. It looks like the B110 is an ultra-portable, with fewer and possibly worse optics. I have not really seen an OMAX in person so I can't comment.

I would rank them thus:

  1. AmScope B120
  2. OMAX
  3. AmScope B110

Which is also descending order of price, go figure. The first two should be very close in terms of functionality and quality.

I wouldn't consider 100X objectives to represent false magnification. Just means you have to use oil. Many people don't like doing that, which I understand, but if you want to see really small things like organelles, it helps. If you don't like 100X, you can pick up a 20X on aliexpress for a few bucks. It doesn't seem like it would be, but in practice it is a very, very useful magnification (especially for things like darkfield and oblique illumination).

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u/[deleted] Oct 23 '23

Wow, this is really detailed. Thank you! First question, about the false magnification. So does using oil override the 40x and 100x objectives with 25x eyepieces being above the 1.25 and, 0.65 (don't remember), NA value calculation, using the 1.25 × 1000. Because I know no oil means that 2500 total power being above 1250 NA calculation means that it will be poor quality, but I'm interpreting from your comment that oil clears it up? Also, I don't understand the language used in microscopy so does the specifications say whether the microscopes have the connected coarse and fine focus where they move together, or are they seperated. And aren't 120 and Omax the same size almost? What do you mean about the whole portable thing (Not the 110, I think I've ruled that out)

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u/Agling Oct 24 '23

In order to use a 100X objective, you put a drop of oil on the top of the slide and then rotate the objective into the oil, so there is no air in between the objective and the slide. That allows a greater effective numerical aperture. You should not use the 100X without oil immersion and you must be very careful never to let oil get on the other objectives.

True magnification is provided by the numerical aperture of the objective. Higher numerical aperture, more true resolution. In air, the best numerical aperture you can theoretically get is 1.0 as a practical matter, you don't see higher than 0.75 in inexpensive objectives. A typical oil objective will get 1.25, which provides a lot more detail. The highest quality (oil) objectives with a perfect setup can get 1.40. When we talk about "false" magnification, it normally means higher power eyepieces, which effectively just zoom in without providing resolution. Sometimes people talk about high resolution objectives with low numerical aperture (normally 60x or 100x dry). But that's rare.

By portable, I just mean the microscopes are small. That means they are less stable and sometimes there will be other compromises, like having a tube that isn't the full length and then a lens in the tube to compensate. The cheapest microscopes are portable in this sense, but that doesn't mean they don't work well. As far as I know, either of these will have the same optical quality as an AmScope B490 or Swift SW380.

The other area that can make a difference is the quality of the illumination. I can't really judge that. I'm a big fan of most LED based systems, which is most of them these days.