Yes, you can turn your phone into a microscope, within limits. A phone camera on its own focuses no closer than a few centimetres, but adding a small, strong lens in front of it lets it focus on objects a few millimetres away and magnify them. With a good add-on lens you can see salt crystals, insect eyes, the subpixels of a screen, pollen and, with some care, large plant cells. A phone on its own won’t give you the clear, high-magnification view of a real compound microscope. It can’t show detail inside bacteria, and it certainly can’t show viruses.
There are four main ways to do it:
- Hold or clamp the phone to the eyepiece of a real microscope: the best image quality by far.
- Clip a macro or “microscope” lens over the phone camera: cheap, portable, good for surfaces.
- Make your own lens from a laser-pointer lens, glass bead or drop of water: almost free, fiddly but fun.
- Use a paper or stand-type phone microscope: a middle ground for transparent specimens on slides.
Option 1: Use your phone with a real microscope
If you already have a microscope, your phone is an excellent camera for it. This is often called digiscoping.
- Focus the microscope on your specimen as normal, looking through the eyepiece.
- Open the camera app. Hold the phone lens centred over the eyepiece, a few millimetres above it, roughly where your eye would be.
- Move the phone slowly until the dark circle on screen fills out into a full, bright image.
- Tap the screen to focus and adjust exposure, then take the photo.
Holding the phone steady by hand is hard, so many people use an inexpensive phone adapter that clamps the phone to the eyepiece. It keeps everything aligned and lets you take video of moving organisms. This approach gives you the full resolution of the microscope’s objectives, so you can photograph cells, protozoa and stained slides at 400x and beyond.
Option 2: Clip-on macro and “microscope” lenses
Clip-on lenses attach over the phone’s camera with a spring clip or a sticky pad. They range from mild macro lenses to strong “microscope” lenses sold with claims of 60x, 100x or more.
- Good for: surfaces and small objects: fabrics, banknote microprinting, printed dots, insect parts, leaves, crystals, screen pixels, coins, skin and hair.
- Limits: the higher-power ones have a working distance of only a millimetre or two and a very shallow depth of focus. Most also need you to light the subject yourself, because the phone and lens block the room light.
- Tip: phones with several rear cameras may pick the wrong one when you’re very close. If the image goes blurry, try switching lenses manually in the camera app or using a “macro” mode if your phone has one.
Many phones also have a built-in macro mode. It’s handy for close-ups of flowers and insects, but it magnifies much less than a strong add-on lens.
Option 3: Make your own lens
You can build a phone microscope at home. The Exploratorium’s well-known “Cell Phone Miniscope” uses a small lens taken from a laser pointer (sold as a laser collimating lens) held over the phone’s camera with a ring of poster putty. The method in short:
- Roll a pea-sized piece of poster putty into a thin sausage and wrap it around the edge of the lens.
- Rest the lens on your fingertip and bring it to the phone’s rear camera. A dark circle on the screen helps you centre it.
- Press it gently into place over the camera lens. When it’s centred, a fingertip held against it will make the whole screen glow evenly red.
- Bring the phone close to your subject, a few millimetres away, and move it slowly until the image is sharp.
Other DIY options:
- A small glass bead (a few millimetres across) works as a very short focal length lens, similar to the single-lens microscopes of Antonie van Leeuwenhoek.
- A drop of water on the camera lens bends light enough to magnify a little. It’s the easiest experiment of all, but the image is soft and the drop doesn’t last.
Be gentle with the phone’s camera window. Avoid anything abrasive, and clean off putty residue with a soft cloth.
Option 4: Paper microscopes and phone stands
Paper microscopes such as the Foldscope use a tiny ball lens mounted in folded card. You slot a microscope slide into the paper frame, hold it up to a light, and look through it or put your phone camera against it. Because light passes through the slide, you can look at transparent specimens such as onion skin and pond water, not just surfaces.
Stand-type phone microscopes hold the phone horizontally above a small stage with a light underneath. They’re more stable than hand-held options, which helps a lot at higher magnification.
What you can realistically see
| Subject | Clip-on or DIY lens | Paper microscope | Phone on a real microscope |
|---|---|---|---|
| Screen subpixels, printed dots, fabric | Yes, very well | Hard (opaque) | Yes, with light from above |
| Salt, sugar, sand grains | Yes | Yes | Yes |
| Insect eyes, wings, scales | Yes | Wings, yes | Yes |
| Pollen grains | Shape only | Yes | Yes, in detail |
| Onion skin cells | Possible with backlighting | Yes | Yes, in detail |
| Pond protozoa (e.g. Paramecium) | Difficult | Yes, as moving shapes | Yes |
| Tardigrades | Difficult | Sometimes | Yes |
| Bacteria | No | Tiny dots at best | Only at about 1000x with oil and stain |
| Viruses | No | No | No (need an electron microscope) |
For more ideas on what to point your lens at, see what everyday things look like under a microscope.
Why magnification numbers mislead
Phone lens packaging often promises large numbers. Treat them with caution, for three reasons:
- There’s no standard way to measure “magnification” on a phone. The figure might compare the size on screen with the real size, and that depends on how big your screen is.
- Digital zoom adds no detail. Zooming in on the screen just enlarges pixels. Two very different lenses can show the same “magnification” while one shows far more fine detail.
- Resolution matters more than magnification. Resolution is the smallest detail you can tell apart. A cheap, simple lens has aberrations that blur fine detail however much you enlarge it. A good microscope objective is a carefully corrected multi-element lens.
A practical way to check what your setup really does is the Exploratorium’s ruler trick. Photograph a millimetre ruler and count how many millimetres fit across the screen. That’s your field of view. If 4 mm fits across the screen and eight salt crystals sit side by side across it, each crystal is about 0.5 mm wide.
Tips for sharper phone micrographs
- Light it well. For surfaces, use a desk lamp or a small torch from the side. For transparent specimens, put the light behind them: hold a slide up to a window, or rest it over a small torch or tablet screen showing plain white.
- Keep it still. At high magnification the slightest movement ruins focus. Brace your hands on the table, use a stand, or build a simple support from books.
- Focus by moving, not by tapping. With short working distances, sliding the phone a fraction of a millimetre works better than relying on autofocus. Some phones let you lock focus.
- Use the timer or a volume-button shutter so pressing the screen doesn’t shake the phone.
- Shoot video and pick the sharpest frame. It’s often easier than getting one perfect photo.
- Keep the specimen flat and thin. For wet specimens, a coverslip helps. Our guide to making a wet mount without air bubbles covers the technique.
Is it worth it, or should you buy a microscope?
A phone lens is a great, low-cost way to explore surfaces and small objects, and it’s fun for children. Our list of what kids can look at under a microscope works well with a clip-on lens. It’s also handy outdoors, where you can’t take a microscope.
If you want to see cells properly, watch pond life, or try projects like finding tardigrades in moss or an iodine-stained onion cell slide, a basic compound microscope will give much clearer results. Your phone then becomes the camera for it, which is arguably the best use of all.