Critically shutter speed and ISO are controlled automatically by the camera in live view and movie mode, although pressing and holding AEL for the duration of the shot prevents them from changing.
Take a shot at F8 and then enter live view, set aperture to F1.4 and hit record – the manual states it should record at F1.4, the screen is telling you “F1.4” and yet the movie is being shot at F8!
The old D300 bug also affects movie recording – when you enter live view to record a movie, you can adjust the aperture but the camera will ignore it.
Due to a bug present since the D300 the camera won’t apply the aperture change via the body to the lens if you are changing the aperture whilst in live view mode, even though the information display on the LCD shows the aperture value changing, the camera always uses the last aperture value set whilst using the optical viewfinder.
To compound that issue, there is no exposure meter so if you use manual shutter, ISO or aperture in live view you have to guess what the exposure is going to look like.
In P/S/A mode the display accurately simulates exposure like every other camera, but in M (manual) mode it gives up.
It is clear that Nikon’s philosophy to live view and movie recording so far has been that this function is only there to facilitate the point & shoot ease of use like a compact, because in terms of manual control their live view is as bad for stills as it is for video. The purpose of this article isn’t to slam Nikon but to draw attention to exactly what needs fixing. The D7000 meanwhile just had a firmware update, which doesn’t fix anything. We told them but they didn’t listen! The D5100 has all the same live view problems as the D7000, one bug has even been around since the D300 and they haven’t fixed it.