If the speeds from 1/15 and above are good, your camera is as useable as any camera that I have. You're good to go! Even if you're shooting long exposures at night, 'B' is your friend. I'll bet that very few people use the speeds below 1/30 on your usual 35mm SLR cameras. We generally use SLRs for out-and-about shooting (handheld), and anything below 1/30 is pretty iffy for that sort of thing. Even if you're shooting portraits inside in low light w/ the camera on a tripod, the sitter's small motions make anything below 1/15 problematic. Glad you got it nailed down as to what is, and what isn't, working correctly.