Previously I have shot interiors armed with my Sigma 10-20mm on my XT, the pictures were okay but I knew there was more I could do to enhance my photos. Previously before I shot with these settings; ISO: 400 or 800 TV: 0"3 WB: Tungsten I felt I wasn't getting the full potential of a room so now I ask the following... 1. What is the right aperture for shooting interiors? 2. Would a speedlight help naturally light up a space, as compared to standard flash? 3. What evaluative mode should I use?