Why Is My Long Exposure Overexposed in Daylight?

Likely causes

• ND filter too weak for the desired exposure length. a mild ND filter doesn't cut enough light to allow a multi-second exposure in full daylight without overexposing.
• Not recalculating exposure time after adding a filter. using the same base exposure time with a filter attached, rather than the adjusted time, leaves the shot several stops too bright.
• Aperture too wide for a long daylight exposure. combining a wide aperture with an already-long shutter speed in daylight compounds the overexposure.

The fix

1. Calculate the correct adjusted exposure time for your specific ND filter strength rather than guessing.
2. Use a stronger ND filter if the desired exposure time is still overexposed even after recalculating.
3. Narrow the aperture to reduce the overall light reaching the sensor alongside the ND filter.