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10. Contrast methods for Leica DM4000 M
10.1 Incident light
10.1.1 Bright field (IL)
• Switch to the incident light axis (IL) by push-
ing the
TL/IL
function key.
• Select the
BF
(bright field) contrast method
Do so by pressing the
BF
variable key.
Alternatively: press the variable button
CHANGE RL
.
(For details on key assignments, please see
the identification sheet.)
The display indicates
BF
.
• Insert a specimen.
• Rotate an appropriate objective into place.
• Bring the image into focus using the focus
wheel and set the brightness using the
INT
function key.
The brightness values for each objective are
saved.
10. Contrast methods for
Leica DM4000 M
10.1.2 Dark field (IL)
• Switch to the incident light axis (IL) by push-
ing the
TL/IL
function key.
• Select the DF (dark field) contrast method
by pressing the variable button
DF
.
Alternatively: press the variable button
CHANGE RL
.
(For details on key assignments, please see
the identification sheet.)
The display indicates
DF
.
The DF reflector is rotated into the beam path.
• Insert a specimen.
• Rotate an appropriate objective into place.
• Bring the image into focus using the focus
wheel and set the brightness using the
INT
function key.
Notes:
The maximum objective aperture that can be
used for dark field is
0.75
. All objectives with
greater aperture are automatically blocked for
this method ("DF" flashes in the display).
When the dark field method is selected, the ap-
erture diaphragm is opened fully and cannot be
adjusted.
