Well, for starters, photography is art (well, not all photography is - but the photography you'll be doing will have to be art) so when you say will i have to learn about famous artists and artistic techniques... do you mean traditional art, as in painting, drawing, scultpure etc?
Your body of work/practical and theory are completely seperate, so whatever you do in your body of work doesn't affect what you do in theory (unless you choose to use other artists that have influenced you or that you're appropriating in your theory work). So your whole class will probably study the same theory, which will probably being on art from all sorts of medias, styles and time periods as your case studies.
If you want to do independant study of photographers then feel free to, but i'd strongly recommend you didn't do purely photography study for the hsc exam because there's no saying there will be a question that is photography based, as the questions should usually be answered using a wide range of art.
I hope that helps...