I have a Canon Camera 50D and I do also have a Canon Speedlite 580 EX. Lens in my possession are Canon lens 28-135; 17-85, 70-200 (not the expensive one), 50 MM, 1.8, and a 28-105 all Canon Lens.
Christmas holidays is around the corner. There will be colorful Christmas trees decorations in the Church sanctury as well as the shopping malls. I'll be taking family portraits in the sancuary and maybe at the malls. All these shots will be at night.
Question: Since my Canon 50D has a high ISO options, will using my external flash speedlite 580 eX take better colorful photos? If so could you give me suggestion on what lens (above that I have) and settings on my camera to take colorful beautiful portraits at night.