Timing it right

When working with neutral density filters to extend shutter speeds, it’s important to calculate the required length of the shutter speed in order to correctly expose your image. When using a 10-stop ND this is crucial, as the resulting time can be several minutes long, and 30 seconds either way can under- or overexpose an image, meaning you have to start over. Adam experimented with this and used the Lee Filters app on his smartphone to determine the exposure length.