About a year ago I started doing portraits for friends with my T3i, kit 18-55mm and the el cheapo 50mm 1.8. I do newborns and non walking infants indoors and families and walking infants, toddlers and children outdoors. I am getting good results, people are starting to refer me, I am now charging, but not advertising so I do not have too many jobs. Now that I have a portfolio and I am sure I can get good results I want to upgrade my equipment. My current thinking is to prioritize my purchases according to what is going to add the most 'value' to my work. Someone advised me to start with lenses...so I am thinking of buying the 70-200 2.8L IS first since I do not have any telephotos and I adore the boken of telephotos. During the second half of the year I am thinking of buying the Canon 5D Mark III and the 50mm 1.4L, and maybe in a few years a 35mm L . So here are my questions: Can I use full frame lenses with a T3i and if so, will it be 'beneficial' in my work? I would love to hear from other natural light/outdoor family photographers about my plans for my lenses...do you think I can get away with just a a 50mm and a 70-200mm?