Contents
In short
Put the microscope on a firm table, turn the turret to the lowest power (the shortest objective, usually 4x), clip a slide on the stage, turn the light on, and lower the lens close to the slide while looking from the side. Then look through the eyepiece and turn the focus knob slowly to raise the lens until the image is sharp. Centre what you want to see, then click up to the next objective; it should need only a small adjustment. Start at low power every time, and if you can't find anything, go back to low power rather than hunting at 400x.
Almost every "it's all blurry" message we get traces back to the same two habits: starting at high power, and focusing the wrong way. This guide is the ten minutes with a new microscope that avoid both. It covers setting up, focusing on a first slide, using the lights, the differences for a stereo or digital microscope, and keeping the instrument in good order. It's written for the compound microscopes we sell, the LabZZ M101, Rainbow 2L and Rainbow 50L PLUS, but the method is the same for any of them.
LabZZ M101Runs on 2 AA batteries
Rainbow 2LMains adapter and upper light
Rainbow 50L PLUSMains adapter and upper light
Setting up
Take everything out and check the box against the list on the product page. Levenhuk's compound microscopes need almost no assembly; the manual covers the one or two steps, and the K50 kit comes in its own bag. Put the microscope on a firm table at a height where you can look into the eyepiece without hunching; a kitchen table and a dining chair are about right for an adult, and a child will want a cushion or a lower table. Keep it away from the edge.
Plug in the mains adapter if the model has one (the Rainbow 2L and 50L PLUS do; the LabZZ M101 runs on two AA batteries) and find the light switch and the brightness control (the manual shows where they sit on your model). Turn the lower light on. On the Rainbow models there's an upper light as well, which you'll use for solid objects; leave it off for slides.
Turn the turret of objective lenses until the shortest one, the 4x, clicks into place pointing at the stage. Every session starts here.
Focusing on your first slide
Take one of the prepared slides from the kit. Hold it by the edges, find the specimen (a small coloured patch under the cover slip) and put the slide on the stage with the specimen over the hole where the light comes through. Slide it under the two clips so it's held flat.
Now the part that matters. Look at the microscope from the side, not through the eyepiece, and turn the focus knob so the stage and the 4x lens come as close together as they'll go. On the Rainbow models the stage moves up and down; on others the tube does. Either way, bring them close while watching from the side so you can't drive the lens into the slide.
Look through the eyepiece. You'll see a bright circle. Turn the focus knob slowly in the direction that moves the lens and slide apart. Within a turn or so, shapes will swim into view and then sharpen. Stop when they're sharp. If you go past, turn back a little. If nothing appears after two full turns, the specimen isn't over the light: look from the side again, move the slide until the coloured patch sits over the hole, and repeat.
At 40x you'll see the whole specimen. Move the slide with your fingers (slowly; everything moves ten times faster through the eyepiece and in the opposite direction) until the part you want to see is in the centre of the circle. Then turn the turret to the 10x objective. Because the lenses are designed to focus at nearly the same height, the image should be close to sharp already, and a small turn of the knob finishes it. Centre again and click to the 40x. The same small adjustment applies, but be gentle: the 40x lens sits very close to the slide, and this is where people crack cover slips by focusing downwards. On the Rainbow 50L PLUS the 40x objective is spring-loaded for exactly this reason.
If you lose the image at 40x, don't hunt for it. Go back to the 4x, re-centre and climb again. It's quicker every time.
Lighting
The lower light shines up through the slide and is what you use for anything transparent: prepared slides, onion skin, pond water. Start with it brighter than you'd think and turn it down once focused; too much light washes out detail at high power, too little makes the image grey. Under the stage is a disc with holes of different sizes (the diaphragm). A smaller hole gives more contrast and more depth of focus at the cost of brightness, and it's worth clicking through the positions at 100x on a plant slide to see the effect.
The upper light, on the models that have one, shines down onto the stage and is for solid things: a coin, a leaf, a feather, a fabric weave. Turn the lower light off and the upper light on, use the 4x objective (the higher powers can't focus on something thick), and expect a flat view of the surface rather than the 3D view a stereo microscope gives.
Preparing your own slide
Put a drop of water in the middle of a blank slide with the dropper. Add the specimen: a scrap of onion skin peeled from inside a layer, a few strands of cotton, a drop of pond water instead of the plain water. Lower a cover slip onto it at an angle, one edge first, so the air pushes out rather than getting trapped as bubbles. Blot any water from around the edge with a tissue. That's a wet mount, and it covers nine tenths of home microscopy. The N20 NG set includes 24 blank slides and 40 cover slips for exactly this.
Using a stereo microscope
A stereo microscope such as the Levenhuk 2ST is simpler. Put the object on the stage plate (black side for pale objects, white for dark ones), light it from above with daylight or a desk lamp if the model has no built-in light, and focus with the knob while looking through both eyepieces. Adjust the distance between the eyepieces until the two circles merge into one, then focus with your right eye, and turn the dioptre ring on the left eyepiece until the left eye is sharp too. From then on the focus knob does everything.
Using a digital or pocket microscope
On a digital microscope with a screen, lay the object on the stage, switch on, and turn the focus wheel while watching the display. Set the lights low for shiny objects. Use the zoom ring or buttons for magnification and expect the higher end to be digital zoom. For a handheld or pocket microscope, rest its base directly on the object, which fixes the distance, and turn the focus wheel until sharp; holding it in mid-air almost never works.
Looking after it
Dust is the enemy. Put the dust cover on after every session and keep the eyepiece in when the microscope isn't in use. Clean lenses only when you can see a mark through the eyepiece, and only with a blower or a soft lens brush first, then a lens cloth or lens tissue. Never use a tissue or a shirt. Wipe the stage dry after wet mounts. If you've used immersion oil, clean the 100x objective immediately with lens tissue. Keep the microscope out of direct sun and damp, carry it with one hand under the base and one on the arm, and if it has batteries, take them out before storing it for the summer.
Common problems
| What you see | Likely cause | Fix |
|---|---|---|
| A bright circle and nothing else | Specimen not over the light, or focus far out | Look from the side, centre the specimen over the hole, start again at 4x |
| Half the circle dark | Turret not clicked into place | Turn the turret until it clicks |
| Sharp at 40x, blurry at 400x | Slide upside down, or cover slip missing or too thick | Turn the slide over; use a cover slip on wet mounts |
| Image moves when you blink | Eyelash or dust on the eyepiece | Rotate the eyepiece: if the speck turns, clean the eyepiece |
| Grey, washed-out image | Too much light or diaphragm wide open | Turn the light down, choose a smaller diaphragm hole |
| Circles that won't merge (stereo) | Eyepieces at the wrong spacing | Move them together or apart until one circle appears |
FAQs
Why do you start at the lowest power?
Because the field of view is widest and the depth of focus deepest, so the specimen is easy to find and easy to centre. The higher objectives are designed to focus at nearly the same height, so once sharp at 4x you're close at 10x and 40x.
How do I use a stereo microscope for the first time?
Object on the stage, light from above, merge the two circles by adjusting the eyepiece spacing, focus with your right eye, then set the left eyepiece's dioptre ring. Section above.
How do I use a pocket microscope?
Rest it on the object so the base sets the distance, switch the light on, and turn the focus wheel. It won't focus held in the air.
Which way do I turn the focus knob?
Start with lens and slide close together (checked from the side), then focus by moving them apart. That way you can't crash the lens into the slide.
What should I look at first?
The prepared slides in the kit, then onion skin, salt crystals, a hair and a drop of pond water. Our kids' guide has a longer list that works for adults too.
The microscopes mentioned are dispatched from our warehouse in Northern Ireland with a 14-day return period.
