Carlson J. iMovie HD 6 & iDVD 6 for Mac OS X (Visual QuickStart Guide Series) / Changing Shutter Speed

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iMovie HD 6 & iDVD 6 for Mac OS X (Visual QuickStart Guide Series)
Authors: Carlson J.
Published year: 2004
Pages: 24-25/197

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Changing Shutter Speed

Your camcorder doesn't have a shutter in the traditional sense. There's no little door that opens and closes quickly to control the amount of light that gets through the lens. However, camcorders can simulate shutter speed by controlling how quickly the CCD sensors refresh the image being recorded, which is measured in times per second. A normal shutter speed is approximately 1/60th of a second, meaning the CCD samples an image 60 times per second.

Why change shutter speed? Using a higher setting is good for capturing fast-moving action like sporting events. The blur caused by moving objects is substantially reduced at speeds of 1/4000 or 1/8000, creating frames that contain very little blurring ( Figure 3.5 ). You'll need to experiment with your camera's settings, though; a high shutter speed can also make the image appear to strobe, or flash artificially.

Figure 3.5. Higher shutter speeds can make fast-moving objects appear clearer.

Automatic

1/2000 shutter speed

Tips

Faster shutter speeds require more light. If you think of a traditional shutter, not as much light enters the camera when the shutter is closing more times per second. So a dimly lit room can appear even darker at a high shutter speed.
Your camcorder is probably changing shutter speeds without your knowledge. On Auto setting, it detects what kind of light is present, and if it detects fluorescent lightingwhich flickers imperceptibly to our eyes, but can cause havoc on a digital recordingthe shutter speed automatically changes to compensate.

Panning

Film has the great advantage of width: its wider aspect ratio captures landscape images in a way your regular video camcorder can only dream about. (One of the advantages of shooting in HD is that it's always widescreen .) However, you can pivot the camera left or right to shoot that landscape and not disrupt the scene with too much motion. This side-to-side movement is called panning, and is a common tool in a director's box of shots. A similar shot, tilting, moves the camera up and down, though it's not used as frequently.

To pan a scene:

1.	Mount your camera on a tripod for best results, or hold it as steady as you can.
2.	Determine where the pan will begin and end.
3.	Begin recording at the first point, and pivot the camera left or right at an even pace. If your camera is not on a tripod, swivel your body steadily at the hips.
4.	When you reach the end point of your pan, stop recording.

Pan ahead of subjects

A panning shot often follows a subject from one side of the screen to the other, but think of your composition as you do this. Don't just center the subject in the frame. Instead, provide space into which the person can walk by panning ahead of him ( Figure 3.6 ).

Figure 3.6. Frame your shots when panning so that subjects walk into the shot, not out the edges.

Tips

To help stabilize the camera while you're holding it, pull your elbows in close to your body, hold the camera with both hands, and keep a wide stance.
If you're using a tripod, be sure to get a fluid-head tripod. It's more expensive than your standard unit, but allows for much smoother motion.
As it turns out, the biggest problem with panning isn't moving the camera smoothly. Your top concern should be: is the horizon level? If the camera isn't exactly even with the horizon, panning will give the effect of moving uphill or downhill ( Figure 3.7 ).

Figure 3.7. It's either you or the camerathe world just doesn't naturally tip like that.
Panning doesn't have to involve rotating the camera around a central axis. Use a dolly setup (see "Dollying," earlier) to move the camera from side to side.