Originally Posted by Tumbleweed
It has been my understanding that the diffusers are supposed to be used on sunny, cloudless days or any time you have direct sunlight on your chrono. I have used a Chrony brand in the past and am now using a Pro Chrono. I have found that either one was the most accurate and consistent on cloudy/overcast days with no direct sunlight. Even with the diffusers on in sunlight, a guy has to watch for low sun angles on your chrono, can really give you inaccurate readings. I like to shoot early in the morning when there is just enough light for the chrono to operate but no direct sunlight yet. Cloudy days are good too.
Agreed. They definitely work best when not exposed to direct sun. The place I regularly shoot has a roof on it. In the morning the sun comes up from behind the 'shack' and casts a large shadow in front of the shooting position. As long as my chrono is completely in that shadow, it works just fine. As soon as the sun gets on one of the sensors, readings start to get a little 'hinky'