User Guide

490 Series Microscope
AmScope Proprietary Page 21 of 64
2.18 Using Oil Darkfield Condenser Lens (Optional Accessory)
The condenser works with 100X oil objective and low power objectives (4X, 10X, etc) as
well. Immersion oil is needed on top of the condenser lens for darkfield observation.
Immersion oil is needed between the 100X oil objective and slide.
2.18.1 Using the Oil Darkfield Condenser
1. The first step is centering the condenser. Move the 40X objective lens into the
light path.
2. Remove an eyepiece and look through
the empty eye tube, to see the
condenser’s image directly.
3. Use the condenser lens adjustment
knob to adjust the height of the
condenser until the opaque disc is
slightly smaller than the entire image
circle, leaving a ring of light.
Note: The dark spot has a fuzzy edge and will become larger when the condenser
gets closers to the objective. The distance between the top of the condenser
and the objective is about 8mm, when the dark spot shows in the field of view.
4. Turn the condenser’s centering screws to move
the dark spot to the center.
5. Replace the eyepieces.
6. Raise the condenser to the top of its range, just
short of the slide on the stage. The is the optimal
position for darkfield viewing, but can be adjusted
later, if necessary.
7. Adjust the dimmer so the lamp is at maximum
brightness.
8. Place a slide on the stage and focus. Adjust the height of the stage up or
down slightly for optimal viewing, but the condenser lens should be relatively
close to the slide.