A friend of mine has asked that I take his wedding photos. I am a little nervous in being the photographer on such an important occation but I can't change his mind. The lighting inside the church is going to be very crapy. (The windows are tinted yellow). Any tips on producing decent to great quality photos would be much apprichiatted. My photo gear includes a tripod, srl camera, 35 mm lens and a flash. My main questions are should I use flash and what ISO should I use.