Why Camera Focus Matters When Scanning a Code
Blur is a leading cause of failed scans. How focus, distance and steady hands affect whether a code reads.
A QR code is a precise pattern. If the camera cannot focus, the boundaries between modules blur, and the decoder cannot tell them apart.
The minimum focus distance
Every phone camera has a closest distance at which it can focus. If you are too close, the picture stays blurry, however still you hold the phone.
- Move back until the code looks sharp on screen.
- Then move in slowly if the code is small.
Autofocus takes a moment
After you move, the camera needs a short time to refocus.
- Hold still for a second.
- Avoid rapid movements in and out.
- Tap the screen on the code if your camera app allows tap-to-focus.
Why older phones struggle more
Older or cheaper phones may have slower autofocus or lower resolution. They can still scan well if:
- the code is large enough
- the light is good
- the phone is steady
Steady hands
- Brace your elbows against your body.
- Rest the phone on a table or wall if you can.
- Breathe out as you scan.
Clean the lens
A greasy lens spreads light and lowers contrast. Wipe it with a soft cloth.
Fill the frame sensibly
- Do not fill the entire screen with the code. Keep the quiet zone in view.
- Keep the code roughly centred.
Tips
- Find the sharp distance.
- Hold still.
- Clean the lens.
QR Code Scanner is lightweight and made to work quickly, including on older phones.
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