Condenser Adjustment; Condenser Centration - Olympus BHS Instruction Manual

D. Condenser Adjustment
1, Condenser Centration
1) Stop down the field iris diaphragm with
knurled ring ® by rotating in the direc-
tion of the arrow. (Fig. 14)
2) Use the condenser height adjustment
knob @ to move the condenser up and
down until an image of the field dia-
phragm can be seen clearly in the eye-
pieces. The rotation of the knob in the
direction of the arrow lowers the con-
denser.
Field iris diaphragm image
Field of view
Fig. 15
Field Iris Diaphragm
@ The field iris diaphragm controls the diameter of the ray bundle impinging on the speci-
men surface and therefore, by stopping down the field diaphragm until it is slightly
larger than the field of view, it can reduce stray light, which in turn increases image defi-
nition and contrast.
Aperture Iris Diaphragm
@ In order to achieve optimum objective performance, the opening of the aperture iris
diaphragm should be matched to the numerical aperture of the objective in use. It is
often preferable, however, to stop down the aperture diaphragm slightly more than in-
dicated by the objective N.A. This will result in better image contrast, increased depth of
focus and a flatter field.
@ After completing focus adjustment, re- < B 70 — 80%
move one of the eyepieces from the obser- ; p 7207508
vation tube and look into the empty
eyepiece tube. As you stop down the aper- DPening of the
ture iris diaphragm, the image of the iriş aperture diaphragm 人
diaphragm can be seen in the objective
pupil, Adjust the opening of the dia-
phragm to match the N.A. of the objective
in use. If the specimen is low in contrast,
it is recommended to stop down to 70%
~80% of the objective N.A. (Fig. 16)
Objective exit pupil
Fig. 16
12