I need to take a video of someone talking, seated at a table, in a cafeteria, so I'm doing a practice run at home. I have a D90, tripod, and a Rode microphone. I'm using a 50 f1.4 lens. I have good selection of lenses to choose from. My dry run looks ok except that the video looks like it was shot wide open (background blur matches stills at f1.4) and the focus isn't quite dead on. My subject moves a bit. I think I need to shoot at f2.8 or f4 to get some practical depth of field. If I shoot at f1.4 ISO 800 I get 1/60. Shutter speed increases as I stop down in still mode, but I'm not sure what's happening in live view/video. How can I set f stop in video mode? And a few other questions: grain --a D90 gets pretty grainy for stills at ISO 800, but the room I'll be in is just window light. What's a reasonable limit for ISO in video mode? It seems like grain isn't such a big deal because video is a sequence of frames. shutter speed -- video must have a limit on "shutter speed." Hmm... in live view there is no shutter, so what's going on? aperture -- if I want to get a subject "in focus" while they are speaking, what f stop do I need? I'll have them be relatively still. I know people can take decent videos indoors on point-and-shoots with tiny sensors, so it seems that I should have no problem with my D90... but why can't I control aperture? is there a setting I'm missing?