Bausch & Lomb EM-14 Dynazoom Trinocular Microscope

This is another wonderful example of a classic Bausch & Lomb Dynazoom microscope that is adapted for the examination of thicker opaque materials. The stand has been slightly modified by the addition of a spacer block which raises the limb about an inch higher from the base. The stage carrier has been modified so the stage sits a similar distance further from the viewing head, thus providing extra room for the vertical illuminator assembly. The excursion of the stage is such that a specer is needed to lift the sample high enough so it may be focused by the objectives. Minimum distance between the stage and 'focal plane' is about 10mm.

These microscopes are very modular, so it is helpful to state how they are configured. The stand itself features a low-set coaxial coarse and fine adjustment mechanism that is comfortable to use with the hands resting on the table surface. The XY mechanical stage has low-set coaxial control knobs and a pair of removable specimen holders for an unobstructed stage surface. This stage carrier has no provision for a substage system and the base of the stand has cover plates installed where the transmitted light illumination system would otherwise go.

The stand is provided with the most elaborate version of the many tubes that were available for this instrument. This microscope tube has binocular observation and a control knob to switch the light path into a port on the top of the tube. It also features a 1x to 2x continuous zoom mechanism that operates in both the photo and binocular ports. The zoom knob is graduated. The microscope pod may be turned through 180 degrees so the limb of the stand may either be away from or close to the observer (the vertical illuminator prevents continuous rotation). No oculars are supplied. Equiped with a photo-port adapter collar. This collar would be used with various shutter housings that Bausch & Lomb manufactured for their camera systems. No cameras are included.

The vertical illuminator is the most elaborate of the several Bausch & Lomb provided for the Dynazoom. Called the 'Trivert', it has provisions for bright field, dark field, and (when so optioned) polarized light. Please note that no polarized light accessories are included with the equipment! The illuminator has separate field and aperture diaphragms and a slot for receiving filters. A pre-centered GE 1630 lamp provides more-than-adequate light intensity. The lamp includes a Jeffey transformer with continuously regulating transformer. A selector knob next to the beam-splitter swings in a central stop for observations in dark field (field and aperture diaphragms must be fully opened).

The base of the illuminator carries a quadruple nosepiece positioned away from the observer allowing better viewing of the specimen. The objectives are all of a special version with annular lucite collector lenses for the dark field illumination. The objective threads are actually turned into the lucite eliminating the need for a special large-thread objective all threads are standard RMS 20mm. The four 215mm tubelength objectives include:

8x / 0.20 working distance 0.530 inches, largest field-of-view 0.093 inches
10x / 0.25 working distance 0.390 inches, largest field-of-view 0.073 inches
20x / 0.40 working distance 0.035 inches, largest field-of-view 0.036 inches
40x / 0.65 working distance 0.030 inches, largest field-of-view 0.018 inches

The stand is in superb condition cosmetically. The microscope body has been completely rebuilt so the binocular portion interpupillary system works smoothly as well as the zoom mechanism and the viewing port selector. Binocular alignment was touched up so both eyepieces are perfectly coincident. Focus mechanism and stage controls both work very smoothly. Optically, the stand is in superb condition, however there is some minor misalignment of the field and aperture diaphragms in the vertical illuminator. Images are still excellent and I will leave it up to the purchaser as to whether he wishes to address that issue.

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