Hi! As you know you can turn you flash head verticaly -180 -- +90 dec. So I turn -135 dec. to get it pointing UP and behind me. But now I can NOT use my vertical grip (MB-10), because it's pointing DOWN to my shoulder ... And so do ALL (what I know) flash lights.. From my point of view, just wrong way!!!
I'm still not sure what problem you are having. I assume the N90 vertical grip works with the camera turned on its left end. But forget the grip for now. Imagine the camera in horizontal position witht your flash in the camera's hotshoe. No matter how you turn the head of the flash, you should be able to achieve the same result whether the camera is turned vertically on its left side or right side. But you would have to use both tilt and swivel. If you are using a particular bracket, this may not be true. For the nitpickers among us, the flash lens might be turned long-way-horizontal in some cases, long-way-vertical in others.
>I'm still not sure what problem >you are having. I assume >the N90 vertical grip works >with the camera turned on >its left end.
(Been on vacation.. 1.5 weeks)
Hmm.. How to explain.. If you look your flash.. You can turn flash head to right max. 90 dec. and left 180 dec.! OK! If you have camera on vertical position and flash is connected to camera. NOW you have white wall BEHIND you and there is white ceiling too. Now you want to bounce your flash from that wall and ceiling, so your flash should point UP and behind you!!! RIGHT? BUT... You can NOT turn your flash head that direction because is limited to 90 dec. (clockwise) so it is pointing now DIRECT UP! If you turn other ways (anti-clockwise) it is pointing backwards or downwards, BUT not that direction where you want it to be...