Sydney harbour is very scenic area and it is really great place for lighthouses hunters :) Good way to see some of them is to take trip on Sydney Ferries from Sydney (main wharf is Circular Quay in the City) to Manly (suburb of Sydney).
First light on the way will be Fort Denison lighthouse, built in 1913 on the top of 19th century fort (all images below are clickable)


Robertson's Point (1910) is next one on the port side just after Fort Denison.

Next lighthouse is very simular to Robertson Point - Bradley's Head light:


Then to starboard of the ferry - Shark Island light:

In the middle of harbour two lighthouses constructed in the water. Red is Western Channel Pile Light:

And green - Eastern Channel Pile Light