The short answer
Clean the lens properly first, because a smeared lens defeats autofocus entirely and is the cause in most cases. Then remove the case, which can block part of the lens or hold a magnet near the stabiliser. If the camera buzzes or the image shakes, magnets are the likely culprit and they can cause permanent damage.
Phone cameras focus by moving a tiny lens element with an electromagnetic actuator, and stabilise by moving it continuously to counteract hand shake. That mechanism is sensitive to dirt in front of it and to magnetic fields around it, which is why two of the most common causes are things people do not associate with a camera at all.
Cause 1: the lens
Look at the lens in good light
Fingerprints, pocket lint and a film of oil are usually visible at an angle and invisible straight on.
Clean with a microfibre cloth
Dry first. If there is a stubborn film, breathe on it and wipe, or use a barely damp cloth and dry immediately.
Check the case cutout
Which collects debris around the edge and can leave a smear ring on the lens.
Check for a scratched lens cover
Fine scratches scatter light, which reduces contrast and makes autofocus hunt. A cracked cover is repairable on most phones and is a separate part from the camera itself.
Test each camera separately
Wide, ultra-wide and telephoto have separate lenses. One being dirty explains why some shots are fine and others are not.
Cause 2: magnets
This is the cause that surprises people. Strong magnets near the camera interfere with the focus and stabilisation actuators. Symptoms include a buzzing or rattling sound from the camera, a visibly shaking preview, and a camera that cannot hold focus.
Sources include magnetic car mounts, magnetic phone cases and wallets, magnetic charging accessories not designed for your phone, and speakers or tools placed near the phone.
Prolonged exposure can permanently damage the stabilisation mechanism, which is a repair rather than something that recovers. If you use a magnetic mount, use one designed for your phone’s own magnet array rather than one requiring a metal plate stuck near the camera.
If the camera buzzes audibly or the preview shakes when nothing is moving, stop using magnetic accessories near it immediately. That noise is the stabilisation actuator being disrupted, and continued exposure causes permanent damage that only a camera module replacement will fix.
Cause 3: how you are shooting
- Too close. Every lens has a minimum focus distance. The main camera typically cannot focus closer than about 10cm, and the ultra-wide or a dedicated macro mode is what handles closer subjects.
- Low light, where autofocus has little contrast to work with and hunts. Adding light is the only real fix.
- Low contrast subjects, such as a plain wall or a clear sky, which give the focus system nothing to lock onto.
- Through glass, where the camera focuses on reflections or on the glass itself. Pressing the lens close to the glass helps.
- Moving subjects in low light, where the shutter is slow and the result is motion blur rather than a focus failure.
Tapping to focus on a specific point, rather than letting the camera choose, resolves a surprising number of these.
Cause 4: software
- Force close the camera app and reopen it, which clears a hung focus routine.
- Restart the phone, which resets the camera subsystem.
- Clear the camera app’s cache on Android.
- Test with a different camera app, which separates the app from the hardware immediately.
- Check for updates, since camera behaviour is firmware-controlled and regressions occur.
- Turn off any third-party camera effects or filters that might be intercepting the preview.
Cause 5: hardware
If the camera hunts continuously in good light on a clean lens with no case and no magnets, in more than one app, the focus actuator has likely failed. A drop is the usual cause.
Camera modules are replaceable on most phones and the cost varies considerably by model. Running the manufacturer’s diagnostic first gives you a definite result to take to a repair shop rather than a description.
One more thing worth checking: some phones use the proximity or laser sensor beside the camera to assist focus, and a screen protector or case covering that sensor degrades focus performance without touching the lens at all.
Why does my camera buzz and the image shake?
A magnet near the phone is disrupting the stabilisation actuator. Remove magnetic mounts, cases and wallets immediately, since prolonged exposure causes permanent damage.
Why can I not focus on something close up?
The main camera has a minimum focus distance of around 10cm. For closer subjects, use the ultra-wide camera or a dedicated macro mode, which are designed for it.
Why are my photos blurry in low light?
Often motion blur rather than focus failure, because the shutter stays open longer. Hold the phone still, brace against something, or use night mode which is designed for this.
How do I clean a phone camera lens safely?
A dry microfibre cloth, with a barely damp one for stubborn marks, dried immediately. Avoid alcohol and abrasive cloths, which can damage coatings on the lens cover.
Is a camera repair expensive?
It varies by model, and the camera module is a replaceable part on most phones. Run the manufacturer’s diagnostic first so you arrive with a result rather than a symptom.
The order
Clean the lens and check the case cutout. Remove the case and anything magnetic, especially if the camera buzzes. Test each camera separately and try tapping to focus. Force close the app, restart, and test a second camera app. Then check whether a case or protector is covering the focus assist sensor, which is the last cheap cause before a repair.
