Setting Up Your Screen for Accurate Tests
- Go fullscreen at 100 % browser zoom. The patterns are drawn in physical screen pixels. If your operating system scales the display (for example 125 %), the panel tells you which browser zoom restores a pixel-exact image.
- Check the refresh rate. Timing patterns change once per screen refresh, so a 120 Hz or 144 Hz monitor gives finer time steps than 60 Hz. CamTestKit measures the rate and shows a confidence level; on variable-refresh (VRR / ProMotion) screens choose the rate manually.
- Turn brightness up and disable night-light, blue-light filters and auto-brightness so short exposures still record a clean image.
- Mount the camera square to the screen on a tripod and fill the frame. For timing tests, defocus slightly if the screen’s own pixel grid causes moiré.
- Leave the watermark on. It burns the pattern, settings, refresh rate and (optionally) local or UTC time into every frame, so each photo documents its own test conditions.
Keyboard Shortcuts
| Key | Action |
|---|---|
F | Enter / exit fullscreen |
P | Open the settings drawer in fullscreen |
1–6 | Switch pattern |
← / → | Adjust the main setting (frequency, speed, line pairs) |
Space | Pause / resume |
H / W / T | Toggle HUD, watermark, clock mode |
Test Pattern FAQ
Can I use a phone or tablet as the test screen?
Yes. Open the page on the device, rotate it to landscape and tap Fullscreen. Phones and tablets usually refresh at 60 or 120 Hz; if the refresh confidence shows low (common on adaptive-refresh screens), pick the rate manually in the panel.
Why does my monitor refresh rate matter?
A screen can only change its image once per refresh. Timing patterns such as the flicker test, shutter dial and LED matrix therefore have a time resolution of one refresh period: 16.7 ms at 60 Hz, 8.3 ms at 120 Hz and 4.2 ms at 240 Hz.
Are the patterns accurate on high-DPI or scaled displays?
Patterns are rendered at the display’s native device-pixel resolution. When the operating system uses fractional scaling such as 125 % or 150 %, a perfectly pixel-exact image needs a matching browser zoom; the panel shows the zoom level to use.
Do the patterns need an internet connection?
Only to load the page. All patterns are generated on your device in real time, nothing is streamed, and no camera image is uploaded.