The reading says DIFFICULT SOURCE

Meter shows this when the light is flickering, when a gray card is lit by two colors at once, or when the color is past what your camera can read. Treat that number as a starting point.

Step by step

1. Look under the reading for the orange flicker line. If it shows, tap USE to set the flicker-safe shutter it names, or change the light's dimmer setting.
2. On GRAY CARD, switch off one of the two lights, or move the card fully into one of them, and read again.
3. A very warm source, like a candle, can be past what your camera can read. Use that number as a rough guide and test on camera.

If that didn't work

The note appears after about two seconds of a difficult light and stays at least three, so it cannot flash on and off. It does not look at the light's spectrum, so a steady LED with a poor spectrum will not set it off and can still read HIGH. On a light like that, check a gray card on the camera itself.

Last updated October 26, 2026