How To Focus A Specimen

How to Focus a specimen 1. Always start with the __scanning objective___________. It’s the shortest objective. •

Use the _coarse adjustment knob___ to focus. The image may be small at this magnification, but you won't be able to find it on the higher powers without this first step.

2. Once you've focused on Scanning, switch to _Low Power_________. It’s the _medium__________ sized objective. •

Use the _coarse adjustment knob____ to refocus. DO NOT _START OVER____. You should only have to move the knob a little bit. If you aren’t getting it focused easily, _GO BACK__ to scanning and start again. It will take _less time___ than trying to start from scratch. If you haven't focused on this level, you will not be able to move to the next level.

3. Now switch to _High Power_________, the__longest______ objective lens. •

At this point, you should only need to make a little bit of adjustment with the fine adjustment knob to get your microscope focused. You should _ONLY use the FINE adjustment knob in HIGH POWER_____. If it is not focusing – go back to Low or Scanning Power!

4. If the specimen is too light or too dark, try adjusting the __diaphragm________.

6. If you see a line in your viewing field, try twisting the eyepiece, the line should move. That's because it’s a _pointer_____, and is useful for pointing out things to your lab partner or teacher.