Come to think of it, just go to South Station, walk out of the main entrance and make a sharp left walk a couple blocks through the business district, post office square, and before ya know it you'll be in Downtown crossing. There are camera stores galore. For bags, you can shop at any of them.
Thanks. I'm new up here, so though I know South Station, and have been to a T stop called Downtown Crossing, it would be a help if you could tell me the name of one of the stores in that area so I can ask for directions when I'm close, and so forth.