Setting up a trinocular dissecting microscope for best viewing

“Trinocular” means three oculars or eyepieces Ocular tube for mounting a camera Oculars for viewing by eye

easier manipulation of specimens. A stereo “dissecting” scope has two complete lens systems, producing two separate images which are combined in the mind of the observer to produce a three-dimensional image that allows easier manipulation of specimens. Two independent lens systems

Specimens can be illuminated from two light sources; one below and one above, depending on needs of viewing a particular specimen Upper illuminator for “incident light” viewing Lower illuminator for “transmitted light” viewing

Illuminating specimens from below provides for “transmitted” light viewing and from above for “incident” light viewing. One control switch selects the light source and the other varies light intensity. To preserve bulb life, IT IS IMPORTANT to reduce electric current surge by turning the dimmer all the way down before operating the light-source selection switch. Dimmer switch for lights Light source selection switch

Focus and magnification can be varied to produce the best view of a specimen Magnification zoom-control Focus control

Specimens for incident-light viewing can be placed against various backgrounds to improve contrast and feature identification Light-colored stage for dark specimens and dark-colored stage for light ones

To send an image from the dissecting scope to the ocular tube for mounting a camera, a diverter prism is moved out of the field of view on one lens system. This process eliminates the image from one of the viewing eyepieces, and may require repositioning the specimen for best viewing. For viewing through eyepiece For capturing with camera

A stereo dissecting microscope is normally used to view relatively large specimens at magnifications from about 5X to about 50X. The scope provides a very large range of adjustment to accommodate a variety of specimen sizes and to allow many options for specimen illumination.

To accommodate large specimens, the entire focusing head of the scope can be raised on the support column. Small specimens can be accommodated by lowering the focusing head on the support column. The illuminator can be moved to provide light as needed for best viewing. Focusing head Support column

Adjust the microscope eyepieces so you can comfortably see a well-focused image through both Space eyepieces so you can comfortably see through both at the same time. If one eyepiece tube is fixed focus, close the opposite eye and, using the microscope focusing knob, carefully focus an image of the sample for the open eye. (If both eyepiece tubes are variable focus, either one will do.) Now close the other eye and use the variable focus eyepiece tube to bring the image into focus for the open eye.

Focus on the specimen at the lowest Zoom setting and be sure the feature of interest is in the center of the field of view. There will be a much larger field of view but much less detail visible than at higher Zoom settings.

Zoom to the desired magnification level and refocus if necessary Zoom to the desired magnification level and refocus if necessary. The field of view will be much reduced, but the feature of interest will be much magnified.

As with any images used for diagnoses, relative size is extremely important. Whenever possible, a comparative scale should be included with an image, or at least the approximate magnification indicated. cm. approx. 100X

When the microscope has been adjusted to produce the best image of a specimen, it is ready for capturing with the camera. Now the diverter-prism must be pulled into position to direct light up the third ocular tube to the camera mounted on it. REMEMBER What you see in the camera or on the image-capture viewer is what will be saved to a digital file. NOT NECESSARILY what you see by eye through the eyepieces. BE SURE a final focus is made in the camera viewer or on the image-capture viewer.

REVIEW Be sure illuminator dimmer is turned all the way down before selecting a light source on the scope. 2) Once the light source is selected, turn dimmer control up slowly 3) Move focusing head to a position on the support column that allows appropriate focusing 4) Focus on specimen at desired magnification 5) Adjust eyepieces for best viewing 6) Adjust illuminator for best lighting 7) “Zoom” to a different magnification if desired, refocus and readjust light 8) Divert image to camera, reposition specimen and fine focus on camera or image-capture viewer. 9) Capture desired image