One of the developments with Chrony (and probably the other makers, too) is the issue of light. On a clody or overcastr day, they work fine. The challenge is when shooting under a clear blue sky.
The older Chrony units would not (and still don't, if you still have one) under a blue sky. They required the plastic screen be receted above the little windows. You can make a good screen out of the side of a plastic milk jug.
The newer chrony units will work under a blue sky - usually. I still use the plastic screen above the windows because it is there and there is no need to take it off.
