The extensive range of microscopy equipment and techniques are truly bewildering and ever-expanding. In the past twenty years, there have been many revolutions in light microscopy techniques made possible by improvements in optics, detector technology, and computers. When deciding which kind of microscope system to use or purchase, the first consideration is what is most important for the imaging: speed, sensitivity, resolution, multiwavelength discrimination, or cell viability. Many of these requirements are mutually exclusive, so compromises must usually be made. The second consideration is whether the system should be tailored to a specialized application or be a general-purpose instrument. In general, systems with more flexibility in the choice of hardware may be better customized for specialized tasks, but they are likely to have more “technical” problems. Choosing “off-the-shelf solutions” with software that has been through its first teething problems can be more time-efficient. Whatever type of system is being considered, the need to test the instruments using a particular experimental material cannot be overemphasized.

Company representatives demonstrating equipment should be advised about the choice of fluorochromes and magnifications, so that they can bring the appropriate filter sets, excitation sources, and objective lenses. In addition to the biological material of interest, it is worth using sets of slides of fluorescent beads to provide quantitative data for support The first decision is whether to use an upright view from above or an inverted view from below microscope. In general, for live cell work, an inverted microscope offers more advantages if high resolution and multidimensional imaging are required. On an inverted microscope, the specimen is generally more accessible, simplifying the microinjection process and the use of growth chambers and environmental control chambers. Inverted microscopes also offer better mechanical stability for mounting CCD cameras. An inverted microscope is also excellent for viewing pond life under a cover slip. The slide is inverted with the slip facing the objective the cover slip stays attached to the slide despite the downward pull of gravity because of the surface tension created by the drop of water. This eliminates the compression problems experienced with upright stands. In addition, protozoa and other invertebrates that normally move along the substrate quickly move to the upper surface of the slip, providing a much better optical link with the objective. In fact, this is one reason the inverted microscope is such a hit with cell biologists. After citing a few advantages of an inverted microscope, here are also a few of its disadvantages,

First is the cost. Inverted microscopes are not anywhere near as common as a microscope with a standard configuration so there is less competition both in the new and used markets. Further, they are more complex and therefore expensive to build. One has to get an image that is pointing down from underneath the stage up to the eyepieces in front of the microscope and pointing up. One does not have to be an optical engineer to see the complexities of this. All of this adds intricacy and cost to the microscope.Another disadvantage is that the maximum magnification available on an inverted microscope is more limited. Normally 40x is the highest powered objective although Olympus has a 60x objective available on its more expensive model. Oil immersion 100x objectives are often not available. Finally, a mechanical stage is an extra-cost option on my model and finding petri dishes or other containers that exactly fit the holders that come with it are a little bit of chore. However, one can become skillful after some practice at moving the container by hand without the mechanical stage even at high power. This allows following a microorganism more easily through a diagonal or zigzag course through the immensity of a 100 mm diameter petri dish that may have a culture with a depth of several millimeters. On the other hand, whatever disadvantages an inverted microscope has, these are far outweighed by the basic advantage of an inverted microscope to accept a container with a great and relatively long-lived diverse culture of live organisms without any preparation.