How to I accomplish Low Key Photography Like this?

My camera with flash attached will only allow me a shutter speed of 1/200. I'm still getting ambient light on my images. I have a Nikon D5000 and a SB 900 I'm using my 35mm 1.8G lens… Any tips?

Didn't look at the video, but I can think of three solutions (you might need a combination of the 3.

If you're not already, use the flash in manual mode. And then just crank up the power. The auto flash mode will probably try to maintain some ambient light. Using the flash manually will allow you to control the flash intensity more precisely.

Turn down/off the other lights. Ofcourse this is only possible indoors.

And the final thing is increase the distance between the subject and the background. This final point assumes that your problem isn't ambient light, but the flash itself, the issue is that flash lights evenly and light falls off gradually, so if the background is too close to the subject the flash will also light the background.

Keep in mind that despite the title of the video, low-key photography is not possible everywhere. For instance it's virtually impossible to do low key photography while shooting with the sun behind your subject (Problem being ofcourse that you would need a flash bright enough to overpower the sun).

You can still do this at 1/200th, but you will need in stop down your lens more.

The simplest way is to start by underexposing 2 stops without the flash to get the background black, and then turn on the flash to expose the subject properly. Make sure your shutter speed is 1/200 or slower.

The trick is making sure your flash doesn't inadvertently light the background also. You do that my making sure you subject is a good distance from the background. The way to do that is to make sure the subject is at least halfway between the camera and the background. This means that the light hitting the background will only be 1/4th (or two stops less) of the light hitting the subject.