National DM-52 Instructions Manual page 5

4. Rotate focus knobs to move stage down (away) from objective lenses as far as possible.
5. Turn the objective turret until the 4x (smallest) objective lens "clicks" into position in the optical path.
Each time that you change from one objective lens to another you should turn the turret until you hear
the "click", which indicates that the lens is properly indexed in the optical path.
6. Place specimen slide, cover slip facing up, on stage with specimen centered over condenser lens in
middle of stage.
7. While looking through the eyepiece, rotate focusing knobs until specimen comes into focus. If image
does not appear in field of view, move gliding stage slightly until image appears in field of view.
8. Changing magnification.
A. Rotating objective turret until different objective lens is moved into optical path changes
magnification. Always turn turret until you hear the "click", indication that lens is properly indexed.
Otherwise, you will not be able to see anything when looking through the microscope.
B. See chart below for magnifications provided with your microscope.
OBJECTIVE
4x
10x
40X
C. Also note that each objective has a color ring, which permits you to instruct changes in
magnification by referring to an easily observed color rather than to a number.
D. Microscope has been parfocalled at the factory, which allows easy change from one magnification
to another, requiring only a small adjustment of the focus knobs.
E. As magnification is increased, the field of view (area of specimen seen through the microscope)
will decrease. That is why it is easier to find the specific area of interest on the specimen by
starting with the lowest 4x objective lens, before increasing magnification with the 10x or 40x
objective lens.
NOTE: Care must be taken when rotating the 40x objective into place. This lens has a spring
retractable mechanism, which retracts slightly into its housing if the front of the lens, strikes the
specimen slide. The rack stop has been adjusted at the factory to assure the 40x lens will clear
the thickness of a normal specimen slide and cover slip. However, if the rack stop has been
improperly adjusted, or if using a thicker than normal slide or cover slip, moving the 40x lens too
quickly or carelessly could cause damage to the front lens element or to the slide.
F. Do not let the front lens element come into contact with a wet slide surface, as any contact with
any moisture could damage the lens. If lens is exposed to moisture, promptly wipe with soft tissue
to remove moisture.
MICROSCOPE SPECIFICATION CHART
COLOR CODE RING
Red
Yellow
Blue
5
MAGNIGICATION
with WF 10X Eyepiece
40X
100X
400X