Adjusting The Aperture Diaphragm; Adjusting The Aperture Diaphragm Opening Using The Condenser Scale; Adjusting The Aperture Diaphragm Opening Using The Centering Telescope (Optional) - Nikon Eclipse 50i Instructions Manual

Adjusting the Aperture Diaphragm

3.10
The setting of the aperture diaphragm affects
optical image resolution, contrast, depth of field,
and brightness. Turning the condenser aperture
diaphragm ring (or aperture diaphragm knob)
changes the size of the aperture diaphragm.
A small aperture diaphragm opening reduces
resolution and brightness but increases contrast
and depth of field. A large aperture diaphragm size
increases resolution and brightness but reduces
contrast and depth of field. These characteristics
involve inherent tradeoffs and cannot be optimized
independently. Generally, aperture settings that are
70 to 80% of the maximum aperture of the
objective will provide satisfactory images with
suitable contrast.
Since an excessively small aperture diaphragm
opening will degrade image resolution, we do not
recommend setting the aperture diaphragm to less
than 60% of the objective's maximum aperture.
Adjusting the aperture diaphragm opening using the condenser
3.10.1
scale
Since the condenser scale indicates the numerical aperture set, adjust the aperture diaphragm
ring according to the scale.
(Normally, the index on the aperture diaphragm ring should align with a scale line that
corresponds to 70 to 80% of the maximum aperture of the objective.)
Adjusting the aperture diaphragm opening using the centering
3.10.2
telescope (optional)
Remove one eyepiece lens and mount the centering telescope in place using the optional adapter.
Turn the aperture diaphragm ring to stop down to the minimum aperture. While holding down
the flange of the centering telescope, turn the eyepiece of the centering telescope and focus on
the aperture diaphragm.
Turn the diaphragm ring to adjust the aperture. (Normally, the aperture diaphragm should be
adjusted to around 70 to 80% of the size of the field of view.)
After the adjustment, remove the centering telescope and adapter and reinstall the eyepiece.
Chapter 3 Individual Operations
3.10 Adjusting the Aperture Diaphragm
46
Aperture diaphragm knob
The maximum numerical aperture is
indicated on the side of the objective.
Plan 40X
40x / 0.75
/ -WD
Nikon JAPAN
Plan 40x
40x / 0.75
/ -WD