I have found it's more the angle of the light, than the actual light itself. At the range where I shoot, if I go in the morning, it works fine. But afternoon light, be it cloudy or sunny, gives me a lot of errors. I have since done all my chronographing in the morning.thearborbarber said:There are times I wish I would shoot my shooting chrony. It can be so picky on light but it still works..............sometimes.