Hi, I'm looking to buy a few speedlites, I was wondering if anyone might be able to make some suggestions I could research. Here's the spec. I need them to conform to: 1) Cheap. The price of a used Vivitar 283 would be perfect. 2) I'm after a few of these for studio use and constantly recharging batteries will drive me insane, so mains powerable would be awesome. 3) Must be manually adjustable from 1/1 to 1/32, or better 1/128. 4) Flash duration must be as fast as possible - 1/1000 (t.5) at 1/1 or quicker would be ideal. I already have a Nikon SB-800 which is perfect, but too expensive by far to be buying 6 of. I'll only ever be triggering these wirelessly, so no problems with trigger voltage. Any suggestions? I'd be quite happy to go with Vivitar 283's if it's possible to get past the batteries. Really appreciate any help you might be able to offer. David.