p.s. Ed, if you're shooting in a studio, always try and shoot tethered where possible, mostly because a studio is either costing you or your client, (or both) a decent amount of money, so the last thing you want to do is end up finding out the focus is off in a crucial shot. It's software dependent obviously, but if you're running lightroom aperture etc on a laptop or computer they normally support tethered shooting for most nikon and canon models, and long cables aren't usually more than £20.
p.s. Ed, if you're shooting in a studio, always try and shoot tethered where possible, mostly because a studio is either costing you or your client, (or both) a decent amount of money, so the last thing you want to do is end up finding out the focus is off in a crucial shot. It's software dependent obviously, but if you're running lightroom aperture etc on a laptop or computer they normally support tethered shooting for most nikon and canon models, and long cables aren't usually more than £20.