58
Linear measurements
Linear measurements
The following are required for linear
measurements:
– Graticule with scale division in eyepiece (Fig.
42) or HC FSA 25 PE tube with diapositive
overlay device
→
p. 68 or a digital linear
measuring eyepiece.
– Stage micrometer for calibration.
Micrometer value
The micrometer value of the objective-eyepiece
combination used must be known before the
measurement, i.e. the distance in the specimen
that corresponds to the length of a division on
the graticule used.
Calibration:
Align the stage micrometer and the graticule
parallel to each other by rotating the eyepiece
and adjust the zero marks of both scales to
exactly the same height (Fig. 42).
Read how many scale divisions of the stage
micrometer correspond to how many on the
microscope scale (graticule) and divide the two
values to obtain the micrometer value for the
total magnification in use.
Example:
If 1.220 mm of the stage micrometer corresponds to 50
divisions of the measurement scale, the micrometer
value is 1.220 : 50 = 0.0244 mm = 24.4
µ
m. For extremely
low objective magnifications it may be that only part of
the measurement scale can be used for calibration.
Imortant: If using the magnification changer
(46.1):
Remember to take the additional magnification
value into consideration! We strongly
recommend you calibrate each objective and
each factor of the magnification changer
separately instead of extrapolating the
micrometer values of the other objectives or
magnification steps from the calibration of one
objective. Measurement errors may occur if the
eyepiece is not pushed into the tube as far as
the stop.
Particularly large object structures can also
be measured on the stage with the verniers
(0.1 mm); the distance to be measured could
be calculated from a combined x and y
measurement.
Summary of Contents for DM L
Page 1: ...Leica DM L Instructions...
