I have a Pentax K20D and want to take semi-formal/formal group shots (at tables; small groups etc); at night, low to medium lighting (as in a large ball room or conference dining room).
Another photographer is handling the more formal award presentation shots;
I am doing the "social" shots.
(I do have a Sigma 18-50mm F3.5-5.6 DC and am not sure if it will be good enough)
Can forum members recommend a lens and a flash unit that would suit this sort of work. I am not a professional, but greatly enjoy this sort of work.
My usual photography is of surf life saving competition http://janjuc.redbubble.com/