Join Jeff Sengstack for an in-depth discussion in this video Setting proper exposure, shutter speed, and focus, part of Video Journalism Shooting Techniques.
In this section of tutorials, I want to go over some standard still-photography techniques that also apply to shooting video. Topping the list is setting a proper exposure, shutter speed, and focus. Now, most camcorders can handle those three things automatically, so why bother doing it manually? Well, mainly to exercise more control over quality. Now shutter speed, exposure, and focus are all connected. You change one, you probably have to the change the other two. But the results are better-quality video. The standard way to adjust exposure is by changing the iris, a.k.a. the aperture setting.
Iris, or aperture, uses what are called f-stops. Smaller numbers like f2 mean the Iris is wide open and lets in more light. Higher numbers--f22 or f32 for example--let in much less light. Changing the aperture changes what's called the depth of field, the distance between the farthest and nearest objects in the scene that are in focus, which is also dependent on where you set the focus and how far your subject matter is from you. A wide-open iris has a narrow depth of field, down to just a few inches. A small iris has a much greater depth of field. At f32 virtually everything will be in focus.
A shallow depth of field creates a film or portrait look, and that way you can just have the subject in focus with background and foreground objects out of focus. Shutter speeds in still cameras and video cameras work more or less the same. Video camcorders shoot some number of frames per second, usually from 24 to 60. Think of each frame as an individual photograph. Fast shutter speeds in the 1000th-of-a-second range freeze action. Slow shutter speeds--1/30th of a second, for example--can lead to blurred images. Shutter speed and iris settings work hand in hand.
For example, if you close down the iris setting, that means you need to slow down the shutter speed to compensate for the decrease in light getting to the lens. As you adjust iris settings, you'll also need to consider focus. For example, if you're working outdoors you can have a high f-stop setting, which closes down the iris and expands the depth of field. That means you can set your focus at a middle distance and everything will be in focus. If you're shooting in low-light conditions with a wide-open iris with a shallow depth of field, you really need to pay attention to the focus. Most higher-end camcorders offer up a couple other ways to deal with lighting conditions.
Neutral-density filters are helpful if you want to have a shallow depth of field under bright conditions. ND Filters cut the amount of light coming into the camera, so when you compensate for that by opening the iris, that creates a shallower depth of field. And some camcorders have a gain control that increases the sensitivity of a pickup device. The downside is that gain introduces noise or grain into your video. How you set the exposure, shutter speed, and focus varies from camcorder to camcorder, but all camcorders let you eyeball the results of those change settings in the viewfinder and some camcorders go beyond that by offering up scopes and other visual aids as extra guidance.
Some, for example, offer what's called zebra striping to indicate areas that are overexposed. Overexposed areas are also called super-whites and they have no detail, and you want to avoid that. Seriously underexposed areas are black and also have no detail. But if you're concerned you might not have the exposure just right, do avoid overexposing your clips. In general, using post-production color correction techniques it's easier to retrieve details in darker areas than just to recover details in overexposed regions. Changing your shooting routine from fully automatic to fully manual might be too much to do all at once.
So rather than going cold turkey, you might to consider turning off only one of the automatic features. I suggest you start by turning off auto iris. That should ease you into the realm of manual controls.
- Creating effective stories
- Planning the shoot
- Setting proper exposure, shutter speed, and focus
- Adhering to the rule of thirds
- Framing the shot
- Achieving a good color balance
- Keeping shots steady
- Using smooth zooms and pans
- Establishing opening and closing shots
- Transitioning from exteriors to interiors
- Editing cutaways
- Using lights
- Using trucking shots
- Working with audio