Olympus BX51 - Page 23

BX51
19
· The aperture iris diaphragm determines the numerical aperture of the
illumination system. It has an effect of adjusting image resolution and
contrast. Stopping down the aperture iris diaphragm increases the depth
of focus.
· Since the contrast of microscope specimens is ordinarily low, setting the
condenser aperture iris diaphragm to between 70 and 80% of the N.A. ²
of the objective in use is usually recommended.
Adjust the ratio by removing the eyepiece and looking into the eyepiece
sleeve while adjusting the aperture iris diaphragm ring @ until the image
shown in Fig. 31 is seen.
}Using the numerical aperture scale:
You can use the condenser numerical aperture scale by adjusting the
aperture iris diaphragm ring @. (Fig. 32)
Aperture iris
diaphragm image
Fig. 31
Fig. 32
Objective
Magnification
Condenser
Abbe
U-AC2
Achromat/aplanat
U-AAC
Swing-out
U-SC3
Ultralow magnification
U-ULC-2
1.25X
Applicable to FN 22
2X
Applicable (FN 26.5) by
moving top lens out of
the light path* (FN 26.5)
4X
Applicable to FN 22
10-60X
Applicable
(FN 26.5)
Applicable
(FN 26.5)
Engage top lens in
light path (FN 26.5)
100X
Applicable
(FN 26.5)
N.A. scale
@
²
Objective pupil
70-80%
30-20%
Aperture Iris Diaphragm (Figs. 31 & 32)
2 Compatibility of Objectives and Condensers
* When using the U-SC3 swing-out condenser together with a 1.25X to 4X objective, fully open the condenser aperture iris
diaphragm and use the field iris diaphragm in the base as aperture diaphragm. With the 1.25X to 2X objectives, the
surroundings of the field of view may become dark.
}To obtain better illumination in photomicrography using a 1.25X to 4X objective, use of the U-ULC-2 is recommended.