Microscopes are incredible tools that can be great fun to use and a way for you to explore things too small for the human eye to see.
Using a microscope is a skill that often takes years to perfect, and there are many little mistakes you can make that cause blurry images and ruined samples.
If you’re new to microscopes you might be wondering how to get the perfect focus for the specimen you wish to observe.
If this sounds like you, then don’t worry – you’ve come to the right place! In this article, we’re going to give you a comprehensive guide on how to focus a microscope.
We’re also going to be giving you some other general tips on microscopes and how to prepare samples, as well as a short Frequently Asked Questions section to answer some of the most common queries around this issue.
Setting Up Your Microscope
In order to properly focus your microscope, you have to make sure that everything is set up right.
Small errors in your preparation can cause unwanted side effects. In this section, we’re going to break down how to set up your microscope.
1. Choose A Flat Surface With Good Lighting
In order for you to have the best experience you can, you’re going to want to make sure your microscope is placed on a flat surface.
A table or desk is going to be your best bet for this, and generally, you want it to be tall enough for you to lean over when observing.
You’re also going to want to have good lighting available so that you can see all of the components of the microscope and specimen.
2. Turn Your Microscope On
Typical Stereo Microscopes tend to have their on-switch at the very base of the machine. Ensure that your microscope is connected to power and switch it on.
From here, a light should turn on at the bottom of the microscope which will aid you in properly observing your specimen.
Preparing Your Slide
You can buy pre-prepared slides that are ready for you to observe with specimens already inside, but if you have a specimen yourself then you can do this on your own.
Properly preparing a slide is going to be one of the most important steps to creating a clear image. Generally, specimens are mounted onto microscope slides that are made of either plastic or glass.
The term ‘dry mounting’ is used to describe the most simplistic technique of preparing a microscope slide.
It’s very simple, all you have to do is place the specimen in the very center of the slide, and then gently lower a cover slip on top. This can then be placed onto the stage of your microscope.
Wet mounting is very similar, used to observe aquatic or living specimens. The only difference here is adding liquid (such as glycerin or water), with a pipette between the mount and slide.
One important thing to note here is that you need to make sure you’re using an adequate amount of water and that (if you want to observe a live specimen) you don’t press too hard on the cover.
Clipping Your Slide
You’re going to need to make sure that the slide is properly clipped onto the stage with the attached clips.
It’s important to note that these clips have been specifically designed to safely secure your glass or plastic clip to the stage without damaging it. Ensure it’s clipped in so that it doesn’t run the risk of moving out of place.
Debris And Dust
To get the clearest image of the specimen you’re trying to observe, you need to make sure that your slide is free of debris and dust.
Small flecks can obscure the specimen, so you need to make sure that you don’t get anything else trapped between the slide and the cover.
You can do this by ensuring that you prepare the slide in a flat, clean place. You can even wear rubber gloves.
Focusing Your Microscope
Properly focusing on a microscope slide takes a lot of time and patience. You’re going to want to work your way up. In this section, we’re going to take you through each step of the focusing process.
You’re going to want to make sure you follow each step carefully.
One of the most common mistakes people make is going immediately to the highest power configuration and turning the knob to focus, but you’re going to want to take your time instead.
Step 1. Adjusting The Stage
The ‘Stage’ is the part of the microscope that can move up, down, left, and right. The goal here is to completely center your microscope around where the specimen is sitting.
Providing you’ve properly centered your specimen in the middle of the slide, this is going to be the part you’ll want to focus on.
If the specimen you’re trying to observe isn’t perfectly in the center, not to worry! You’ll be able to adjust the stage left or right until it’s in the right place.
This can take some trial and error, and this is a step you’ll most likely to repeat once you’ve set up your magnification settings in the next steps.
Step 2. Start With The Lowest Power Objective
To understand power objective, you need to realize that what it really means is the total zoom of your microscope. The higher power objective you set your microscope to, the closer view you will get.
This is where a lot of people mess up because they zoom very far right away without finding the specimen first. To begin, you’ll want to start on the lowest power objective available.
Depending on the location of your specimen on the slide, and how the stage has been adjusted, the image you get is likely to be out of focus.
Take some time to ensure that the specimen is properly positioned before you increase the power object or start turning the adjustment knob.
Step 3. Adjusting The Knob
The turning knob at the side of your microscope. This component of the microscope allows you to focus the image that you can see down the eyepiece, and if you turn it up or down you’ll notice massive differences in the image.
In some ways, you can think of this process as tuning a guitar. Often, smaller movements are going to get you closer to clarity than large ones.
Take some time to play with the adjustment knob and try to find a balance in clarity.
Depending on how accurately you’ve performed the other steps on this guide, you might find that you’re already close to being able to see the specimen clearly, but it’s more than likely that you’ll need to adjust a little.
Step 4. Playing With Power Objective
As you adjust the knob you can also begin to increase or decrease the power objective.
Because we started with the lowest setting, you’re going to want to start going up slowly, trying to find a good balance in both power objective and focus.
Generally, the closer you’re trying to look at a specimen, the higher power objective you’ll need to use and the more you’ll have to focus.
This can take some trial and error, however, so you’ll want to continue to go up or down depending on the image quality you’re getting.
Once you’ve properly focused on the specimen, you can rotate up to a medium or high power objective, which will allow you to see the specimen in even closer detail.
This is the final step, however, and if you find that you’re losing focus, simply go back down to where you were.
Focusing a microscope takes time, effort, and a steady hand.
We would like to once again insist that you take your time and work from a low-power objective and that you properly prepare and center your specimen.
We hope that this guide has told you everything you need to know about how to get a clear image through the eyepiece of your microscope and that you now feel a lot more confident for future observations!
If you have some wider issues, keep reading for our short FAQ that will help answer some common roadblocks that people run into. We wish you the best of luck in your next observation!
Frequently Asked Questions
Why Can’t I See Anything Down My Microscope?
So let’s say you’ve followed the steps in our guide but you can’t see anything at all. This has likely happened for a few reasons:
- The slide is not properly centered.
- You’re way out of focus.
- The microscope is not switched on.
- Your Microscope is faulty.
Go back over the steps we’ve highlighted above and make sure that everything is right. Start on a low power setting, and play around with the focusing knob.
If the image you’re getting through the eyepiece is completely dark, then it’s likely that the microscope is not switched on, or some internal component is broken.
Can You Use A Microscope With Glasses?
If you wear glasses, you’re probably wondering if you’ll be able to use a microscope. You won’t be able to press your eyeglasses to the eyepiece and see anything.
Most observers get over this hurdle by either looking down the eyepiece from above or adjusting the lens so that the image is clear to you. You’re just likely to need some extra adjustment so that you can see it.
Why Is It I can See Dark Circles Down The Eyepiece?
These are actually air bubbles. If you’re observing a specimen in liquid, this is a very common occurrence and something that you can fix by more careful preparation of your slide.
It’s for this reason that wet mounting can be difficult and takes time to create a slide without any air trapped inside.
Why Is The Image Blurry No Matter What I Do?
If you’ve played around with focusing on your specimen and you can’t work out why it’s still blurry, there’s a possibility that your objective lens has scratches or smears.
You can fix this by gently wiping the eyepiece and lens. Be careful not to use any type of cleaning product that can damage the lens.
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