I have Nikon D 7000 usually shoot with a 24 70 or 70 200 and I just got an SB 900. How can I achieve good catchlights outdoors using either the 900 on camera or off camera with the on camera flash as my master and the 900 off camera? I have a reflector but I am talking about those days where it is cloudy or maybe no shade is available. Basically, I need to know at what angle or axis I need to place the off camera flash or can I use the 900 on camera to obtain the catchlights?