There is all kinds of stereo microscopes available in the world market place, so it will be difficult to decide on which one is the best stereo microscope for you.

Stereo microscopes, also known as dissecting microscopes, were designed to provide a three-dimensional view for examining solid samples with complex surfaces at low magnification using incident or transmitted light

You will need a stereo microscope to view more substantial specimens such as insects, bugs, leaves, rocks, gems, etc.

Typically, such specimens require lower power, magnification ranges from 7x-45x. Hence they are also known as low power microscopes. By definition, a stereo microscope has at least two eyepieces (binocular), and provides a three-dimensional image of the specimen. They are available in one of two configurations: dual power or zoom. In the first instance, the microscope has two magnification options, for example 20x-40x. In a zoom microscope, there is a continuous zoom range from the lowest power to the highest power. For example, from 7x to 45x.

As with compound microscopes, stereo microscopes also come in a trinocular eyepieces for photographic purposes. Stereo microscopes can be integrated microscopes or, increasingly often, are modular in the sense that different stereo microscope bodies can be assembled with different bases.

What magnification do I require?

1. Stereo microscope magnifications can range from as little as 2x up to 300x, but typically might be between 20x and 80x, depending on what you are looking at, of course. A common mistake is to believe that you need a higher magnification than is actually required. For many applications, 4x - 20x is enough, though having the ability to go higher may be a desirable feature. As a guide, if you need to view a whole sample, your magnification requirement is likely to be quite low, perhaps no more than 10x. If you will be viewing small details then 40x may actually be more than enough, however up to 80x is also quite common.

Do I need to 'do' anything to the sample whilst being magnified?

2.   If you just need to 'do' something whilst your subject is being magnified, then this can affect your choice of stereo microscope. Different stereo microscopes will have surprisingly different optical specifications, resulting in different working distances (distance from the bottom of the objective lens to the point in sharp focus) and field of view (size of the whole field when looking through the eyepieces). If you are soldering a printed circuit board, it may be more important to have a long working distance, whereas if you are counting items, then a large field of view will be of great assistance.

Do I have any special requirements?

3.   A very open question, but if you need to capture images, or require special illumination (such as UV light), then naturally you need a stereo microscope that can offer these features.

Step stereo microscopes

Fixed magnification stereo microscopes the most basic stereo microscope, therefore being the least expensive (since there is no zoom mechanism). To change magnification, you will need to change the objective (magnification) lens, which typically might be 20x, 40x, 60x magnification etc. Many manipulation tasks can be performed at fixed magnification, so these stereo microscopes are entirely fit for purpose. However, in reality the equivalent stereo zoom microscopes are very inexpensive and with zoom capability are almost always preferred to fixed magnification systems. The illustrated microscope (courtesy of AMZ) has fixed magnifications of 20x and 40x.

Stereo zoom microscopes provide excellent stereo imaging, high levels of magnification, plus a wide zoom range, making these units ideal for "workhorse" type applications, such as printed circuit board inspection, dissecting biological specimens, or similar routine tasks. The microscopes are relatively small, inexpensive, very rugged, simple to use, and easy to maintain. Certain accessories, such as a trinocular head (for image capture) are available, but need to specified at the time of purchase, so are less flexible than the CMO modular design. The illustrated stereo microscope (courtesy of AMZ) has a zoom ratio of 6.4:1 with a standard zoom range of 7x - 45x and a maximum magnification of 180x.