Looking for some help. Recently got a D200 and was out photographing birds at a local reserve. A flock of swans took off from one of the ponds flying straight at me. A great photo opportunity I thought but the camera would not focus. I think it is possibly because the background was the sky. Any suggestions for a remedy for this as I believe I have chosen an incorrect setting option. It is very frustrating to miss good opportunities and it is clearly down to my inexperience with the camera.
As usual any replies and suggestions will be greatly appreciated.