My Sasanqua camellia has brown ends and marks on its leaves and has started to drop leaves and buds. It's early winter here (June) and we have had unseasonal warm and damp weather.
Camellia Leaf Problem
Certified GKH Gardening Expert
The damp or moist weather can cause a couple of different issues for the Camellia.
Here is a link to help you determine which fungus and how to deal with it.