The need for easy visualization and manipulation of specimens and the increasingly widespread use of imaging in biomedical research has led to the development of a new generation of user-friendly, flexible stereomicroscopes. Nikon has catered to research needs with the SMZ line of stereomicroscopes. The SMZ-1500 is their top of the line stereomicroscope based on a modular system, which allows the user to add a whole range of options to a fairly simple basic design. A major difference over previous generations of stereomicroscopes is the inclusion of high quality optics and the easy attachment of cameras and other detection equipment. Key features of the microscope include a wide range of magnifications based on the 15:1 zoom ratio (0.75x- 11.25x), high quality, very long working distance objectives allowing fluorescence imaging and a variety of illumination options for both fluorescence and brightfield imaging.
The optics of the SMZ-1500 are based around a single large objective and a standard parallel design with a set of zoom lenses allowing rapid changes in magnification. Included in the basic microscope body is an iris diaphragm aperture to control illumination intensities. There are a variety of modular options that can be added to the microscope depending on the intended use. Along with two standard binocular eyepieces there is the option of a tilting eyepiece, allowing 30 degrees of vertical tilt and independent movement for each eyepiece. A variety of stands can also be added including simple table stands, a variety of diascopic stands and boom stands to allow movement of the microscope body in virtually any direction. Perhaps the most useful added feature of the SMZ-1500 is the epi-fluorescence attachment, which enables illumination from any lamp with a standard bayonet mount. This attachment also includes a four position slider that holds three different filter sets making it easy to change the light excitation/emission parameters.
The best thing about the SMZ-1500 is its flexibility, robust nature and ease of use stemming from the simple modular design. At the moment, we have several in the lab that are being used for a variety of purposes ranging from delicate animal surgery to quantitative fluorescence imaging of tissues in vitro or in vivo. All of the optics are safely tucked away inside the main body with no small parts on the outside allowing for easy transportation within the lab. It is very user-friendly thanks to the large, stable focus and zoom knobs and requires virtually no training time. In the past, I have compared the SMZ-1500 with comparable models from Leica and Olympus and personally, find that the SMZ-1500 is easier to use and less cluttered. The standout feature of the SMZ is that it is very easy to reconfigure for different uses such as addition of stands, the epi-fluorescence attachment and cameras for detection. The camera port of the epi-fluorescence attachment extends from the side of the microscope, well out of the way of any other controls and a slider on the same side controls light entry. The bonus of offering two parallel light paths is that one path can be sent to camera for imaging while the other can be used with the ocular view.
The main limitation of the SMZ-1500 is that it is neither a high quality standard fluorescence microscope (such as the Nikon TE 2000 / Leica DM 4000 / Olympus BX2) nor a small, simple Greenough design stereomicroscope. As a result, depending on your application there may be better options. For high-resolution quantitative fluorescence, a standard fluorescence/confocal microscope at low magnification would be better. At the highest zoom using the 1.6x or 2x objectives it is sometimes difficult to obtain very clear images because of vibration of the microscope body. Similarly, for simple visualization and manipulation a smaller stereomicroscope would be easier to use.
Overall the SMZ-1500 is a microscope that can cope with a variety of demands. At around $10,000 (not including a light source or fluorescence attachment), it is a bit pricey and could potentially be overkill for a simple visualization task. However, if flexibility is what you are seeking, then the SMZ would be a good option. In our lab, the SMZ is definitely one of the workhorse microscopes and so far has been able to withstand pretty much everything we can throw at it.
Peter Haggie, Ph.D.
Post-Doctoral Fellow
University of California, San Francisco