How to inspect a used phone's camera
Modern smartphone cameras are incredibly complex, often featuring mechanical optical image stabilization (OIS), laser autofocus, and multiple lenses. When buying a used phone, a visual inspection of the glass isn't enough.
What to look for during the test:
- Autofocus hunting: Move your hand close to the lens and then pull it away. The camera should quickly snap into focus. If it pulses in and out ("hunting") or refuses to focus on close objects, the autofocus mechanism is broken.
- Sensor dust (Dark spots): Point the camera at a bright, plain white wall or a blank sheet of paper. Look for faint, semi-transparent gray circles. These are dust particles trapped inside the camera module on the sensor itself. They cannot be wiped off the outer glass.
- OIS failure (The "Jelly" effect): Hold the phone completely still. If the image in the viewfinder vibrates, wobbles, or you hear a physical buzzing sound from the lens, the Optical Image Stabilization mechanism is shattered.
- Front Camera Alignment: Check the selfie camera. If there is a milky haze or a crescent-shaped shadow on one edge, the camera module has slipped out of alignment beneath the screen.
Notice scratches on your lens?
Deep scratches on the outer camera glass will cause severe glare and light flares in photos. You can easily replace the outer glass cover on most phones using an inexpensive kit.
Shop Camera Glass Repair KitsFrequently asked questions
Why is my phone camera blurry?
The most common causes are a smudged lens, a scratched or dirty camera lens protector, a case that partially blocks the lens, or a failing autofocus or optical image stabilization (OIS) module. Clean the lens with a microfiber cloth first. If the image still shakes or refuses to focus, the camera module may be damaged.
What does a rattling camera mean?
A faint rattle when you shake a phone is often the OIS or autofocus mechanism and can be normal when the camera is off. If the preview is jittery, blurry or makes a buzzing sound while open, the stabilization module is likely broken, which is common after drops or motorcycle vibration.
How do I test every rear lens?
Use the Switch lens button in our full diagnostic. Browsers expose each back camera your phone allows. Then open the phone's own camera app and switch between 0.5x, 1x and telephoto zoom to confirm each lens focuses and has no dark spots.
Why does the camera show a black screen?
Camera permission may be blocked, another app may be using the camera, or the camera hardware may have failed. Close other camera apps, allow camera access for the site, and reload. If the built-in camera app also shows black, the module or its cable is faulty.
Is the camera feed recorded or uploaded?
No. The preview and any test photo exist only in your browser and are discarded when you leave the page.