Originally I bought a D5100 because I misread the comparison chart on the Nikon website and thought it could fire a flash remotely (well, it can w/ an SB900, but I bought a SB700). So I bought a used D-90 for $600 (just a bit more than an SB900 would have cost), and I like it a lot. But sometimes it freezes up and I get F--- in the Control Panel where the f-stop should appear. Strangely, I can get the camera to function again by fiddling with controls: changing focus from AF to M; changing OS from on to off; changing the mode. My concern is that in the middle of a shoot some day this strategy will fail and I'll have a dead camera in my hands. Thoughts on this anyone?