We all done it jonny but is not the same as setting the ISO and shutter speed your'e self. 7D has done it perfectly in that matter. whilse in LV you can set the ISO and shutter speed to you're liking and then hit record. You get to see the light changing as you change the setting.
Have you tried to shoot under florescent lighting with D90 and D300s, you get the roling shutter runing down the screen. At low light you get grainy fottage because when you hit LV in D90 and D300s sets the ISO acording the lighting condition so you end up with grainy fottage.
I have tried to point a flash light into the lens to trick the camera to choose the low ISO which in most cases it worked but controllin the SS is pain because you never get it right. You are always guessing the ISO. Locking the exposure only locks the camera to that light reading but doesn't allow you to operate the camera manually.
It is a pleasure to shoot wiht NIkon outside, colors and quality of Nikon is as close as shooting in 35mm motion film cameras, It's just beautifull.
It surprises me how come it is so dificult for Nikon to sort out this problem which to my understanding is very simple. All they have to do is find a link between the camera in still mode and LV, menaning that when camera is in LV mode to use the same settigns from the camera in still mode.
Because at the moment when you hit LV camera goes to auto mode and you can only change the WB and Fstop nothing else. ISO and SS is set by the camera.
I don't know but I wasn't happy when Nikon didn't fix that problem when they brought out the firmware in january becaue I hade few projects lined up which I wanted to shoot wiht Nikon. As I ran a renting company most of my clints started asking for the 7D so i bought it and till now it did pay it self.
I know a lot of you are thiniking using a DSLR shooting video professionaly it is a bit strange but believe it or not here in my country every body is shooting with 7D or 5Dm2 and their clients are happy about it beacue they think is cool how technology has moved forward.
So at the end of the day Nikon has lot a lot for not developing the firmware for those people that have bought D90's and D300s's because we feel let down by Nikon for not hearing our voices.
Nikon should inforce the company that hired to write the firmwares for cameras to see if they can fix that problem even with old cameras like d90 because at the end of the day it makes us the costumers.
So till then I am enjoying my D300s for pictures and 7D for videos.