Hello, if you can only afford 1 lens the best pro level, "multi-talented" lens for Canon is the 24-105 L series zoom. It is the best value lens in the Canon pro L series, yet still about $900 depending on what country you are in. If you feel that the price is prohibitive, OR that you can afford an even better lens I can give you more detailed answers over the phone. Feel free to schedule a chat anytime. Here is my portfolio: www.hemmingshouse.com