Thank you mahleu. Anyone else? some more advice???
You will have a great time, I ran overland expeditions in Africa for 3 years, most of my help would be in finding beautiful little places to go that not many know about but as you already have all your accommodation booked then it's of little help. Highlights for you will no doubt be Namibia, stunning country, especially the coastal areas. Obviously get in to Sossusvlei for the big dunes, Etosha is one of the best national parks I have ever seen. There are 3 main camp sites in Etosha, the best 2 are Namutoni and Okaukuejo, both have fload-lit waterholes and are incredible for the sheer amount of game there to see and photograph. Botswana is amazing too, most go into the Okavango from Maun which is ok but by far the best place is a little spot called Sepupa (this is all from memory so spellings of all these places may be wrong!) It's an incredibly beautiful place right on the river and you can get picked up from the camp site and straight into the Delta and the Mokoro trips, wellworth spending a few days out there. Also from the same camp site you can drive for a couple of hours into the desert and there is a copje which has loads of very old paintings on it, hardly anyone goes there as it's quite hard to find but well worth it. If you want some really good adventure you can drive all the way through Chobe National Park from top to bottom, soft sand a lot of the way and it takes a few days but amazing camping out in the park. Most of the normal roads you take through all the countries you are visiting are very good, I went everywhere just armed with a Micheline map and ask lots of people about local sites. Not much use asking locals for directions as they will just point without really knowing what you want!
As far as photography goes, Africa has an amazing ability to shock and amaze you at every single turn, just look around you, incredible sunsets, beautiful landscapes and loads of wild animals, you'll love it!