Need some advise on food photography, I am using a 30mm lens but finds that i can't auto focus when i am too near the object. Would like to invest another lens should i invest in a 50mm or a 60mm with macro? I read from the Internet, lots of the food photographer is using 50 f1.4, can anyone enlighten me why so? Lastly anyone knows where can I buy a 8" or 12" Collapsible Reflector? Thanks in advance.