The Eclipse E400 biological microscope is Nikon's mid-level research instrument from the late 1990s. Though designed for stability, the instrument features a compact design, which was intended to help maintain a suitable comfort level for the microscopist over extended periods of observation.
The rigid frame of the E400 helps reduce vibrations, a characteristic that is particularly advantageous during imaging for critical photomicrography applications. Head and eye position are also given special attention in the Eclipse design and among the newer features are a lower eyepiece tube angle, an optional eye-level riser, and an optional binocular head, which offers variable inclination angles. A low-profile stage incorporated into the instrument facilitates specimen manipulation and Nikon designers carefully positioned the stage handle and focus control knobs so that they could be operated with a single hand, freeing the other hand of the microscopist for additional manipulations.
The Eclipse E400 features a quintuple revolving nosepiece and Nikon's CFI60 optical system. Included in the system is a series of universal objectives that enable the use of various observation techniques, such as brightfield, darkfield, Nomarski DIC, epi-fluorescence, or phase contrast, without the necessity of changing objectives. Also, since the optics are infinity-corrected, many types of intermediate tubes and accessories, including epi-fluorescence attachments and illuminators, drawing tubes, teaching heads, polarizing analyzers, and eye-level risers, can be inserted into the parallel light optical path between the objective and the convergent tube lens without degrading the image. The magnification capability of the optical system ranges between 10x and 1500x for observation purposes and from 2x to 500x for 35-millimeter photomicrography.