Happy Thanksgiving! So I'm out and about taking photos today. Just using the WL finder. The red LED blinks and I hear beeping. The manual says this means the battery is low. I don't know why that should be; I put a brand new one in a couple of days ago. Anyway, I'm shooting black and white, everything seems normal except for this beeping. When I got back though, I was a little concerned. I took a couple of test shots at f/4, 1/6th. The shutter seemed awfully fast. (Should I be able to discern fractions of a second by sound?) this time though, I used the Polaroid back. Both slow-shutter shots came out pitch black. Now I'm wondering if I'm actually getting something besides he mechanical 1/400. Any suggestions? Are my earlier B/W shots likely black, too?