#2. "RE: Seeking Exposure advice: Nikon D5200 and SB-400 for Indoor wedding tomorrow - June 8th!" In response to In response to 0
I totally agree with Brian. The SB400 is only a little bit bit more powerful that the built in flash. Under the conditions you mention and especially using a diffuser I think you'll be very disappointed with your photos. You'll want to use a higher ISO setting for sure and I would recommend a stronger flash like the SB700.