Using Objective Lens 100 times Direct

When studying or observing bacteria, more efficient to start with the oil immersion lens (100 x) and ignore the preliminary steps with objektif lens with low magnification power. This may by students who are current users / familiar and experienced using a microscope that can skip the use of objective lens and 10 x 40 x before using 100 x objective lens directly.

Tools and materials:

• Preparations of representative microbes: bacteria, fungi, etc..
• Microscope
• lens paper
• Immmersion oil

How it Works:

1. Place the specimen on the slide in the middle of the skylight, just under the oil immersion lens will be placed.
2. Add a drop of immersion oil on the specimen
3. Ensure that there is enough distance between oil and 100 x objective lens before you rotate the lens over the specimen.
4. Set konensor that its position is just below the specimen slide.  Close the condenser diaphragm almost entirely if you see live specimens, otherwise open the diaphragm condenser when viewing the stained specimen.
5. By using makrometer, reduce the distance between the lens immersion oil with the specimen, until the lens is submerged in oil and almost touching the specimen. Working distance for the 100 x objective lens is approximately 0.1 mm.
6. Now see it through a microscope and find the shadow of the specimen by increasing the distance between the specimen and the lens by turning the micrometer.

Move slides forward and back slowly when you are looking for focus. Moving shadow is often more easily seen than the silent shadows. If you do not find the shadow after 3-5 rounds or when the lens is lifted from the oil, repeat steps 5 and 6.

Reasons that are impossible if you do not find anything under the oil immersion lens is as follows:

1. Too much immersion
2. Moving too fast micrometer
3. Condenser is not set correctly (usually a diaphragm iris too open or closed)
4. Dirty lens
5. Too few organisms on the slide
6. Specimens are not attached to the middle of the field before turning the lens
7. Slide upside down.