If better-looking video is your goal, maybe it’s time you took control.
I just paid $400 for an $1,800 camcorder to use in my video courses. One owner, ultra-low mileage, auto, air, power windows–the whole nine yards. How did I get such a deal? The original buyer said it was too much trouble to learn all the buttons, so he swapped it for a point-and-shoot. The kicker is that this guy is actually, literally, a brain surgeon!
I think the moral is that learning camcorder controls is not a matter of smarts, but of interest. To invest the modest effort required, you have to want to take charge of your camcorder–to make videos your way rather than its way.
The first stage in doing this involves learning what your automatic camera controls do, how they do it, and when to tell them, “Please–I’d rather do it myself.” So that’s our topic this time out: we’ll run through the automatic focus, exposure and white balance controls and show you how to put yourself firmly in charge of them.
When looking at these controls, the first question should be why we need them at all. In the case of focus, the answer is obvious. Focusing means adjusting your lens to bend incoming light rays so that they form a sharp image. The problem is that light rays bouncing off an object three feet away bend quite differently from light rays that started 100 feet away. That means that (usually) the lens cannot adjust properly for both distances at the same time.
The solution is to change focus as you shoot. As you pan from the flower at three feet to the tree at 100, you adjust the lens to match. This is easy to do with a still camera, but so tricky to manage with movies that Hollywood shooting crews include a “focus-puller” so that the camera operator doesn’t have to handle the job.
Since you don’t have that luxury, the autofocus control acts as your focus puller. As you shoot, it continuously analyzes the distance to the object in the center of your frame and adjusts the lens focus to match. In almost every consumer camcorder, the unit defaults to autofocus when you turn the camera on, and it works so well that you’ll probably want to leave it enabled much of the time.
When you use autofocus, you’ll get better results if you practice a few techniques to compensate for the fact that even the best systems don’t work instantaneously. If you pan quickly from, say, a distant mountain peak to a foreground tree, the tree will be soft and fuzzy until the autofocus system can determine why the image is soft, determine the focus shift, and crank up the servo motor that makes the actual change in the lens. To avoid this amateurish appearance:
- Never begin shooting the instant you frame the shot. Instead, aim your camcorder at that distant mountain for a few seconds while the autofocus checks it out, and only then begin your shot.
- If practical, include objects at several distances. For instance, in panning from the mountain to the foreground tree, set up the shot so that your frame will move past nearer objects (like a grove thirty feet off) on its way to the close shot. After refocusing for the middle-ground grove, the lens will have a much shorter way to travel to reach its final setting for the close shot.
- Don’t move the camera too fast. Give the system a fair chance to refocus as you pan or tilt the camera.
- Plan to cut out the soft spots. If there is no way for the focus system to keep up with the camera movement, organize your recording so that you can edit the starting and ending frames together as separate shots, eliminating the out-of-focus section in the middle.
By practicing these techniques, you can use autofocus with great success. Well, most of the time, anyway. There are two situations in which the system will ruin your shot. One happens when your subject moves behind a nearer object. When that occurs, the autofocus will dutifully shift to sharpen up the nearer object, throwing your more important subject out of focus.
This can take place when you pan past a foreground object. Suppose, for example, you want to pan across those distant mountain peaks to show the whole range. But there is an unimportant tree in the foreground–as you swing the camera past it, the mountains turn into blurs and then come back into focus as the unnecessarily sharp tree moves past in the frame.
The same thing happens when the subject moves behind a foreground object. Suppose you’re panning with your companions as they stroll along a picturesque street. As they move behind a light pole in the foreground, the pole suddenly sharpens up and your friends and their background all turn briefly to mush.
Both situations are easy to fix:
- First, focus on the center of interest (the mountain range or your friends). You can usually let autofocus do this job for you, before you roll tape.
- Turn off autofocus and make the shot. The camcorder will ignore the foreground tree or lamp post and keep your subjects sharp.
Autofocus can also fail when you start with a wide angle lens setting and then zoom in on a subject. This happens because wide angle lenses keep a much deeper space in focus than telephoto lenses. In bright sunlight, for example, your widest lens setting may sharply render everything from the front of the lens itself all the way to the distant horizon. In identical circumstances, your narrowest (telephoto) setting may hold focus through only a couple of feet of depth.
The problem occurs when you zoom too fast from wide angle to telephoto. Often, the loose and approximate focal setting that is perfectly adequate for wide angle shooting proves too sloppy for the narrower depth of telephoto. The result? The subject that was nice and sharp at the beginning of the shot is a mess by the end of it.
To avoid this disaster:
- Before making the shot, zoom in to the telephoto position and focus carefully on the subject.
- Turn off autofocus.
- Zoom back out the wide angle position and make the zoom shot.
This way, your subject will remain crisp at every focal length between wide angle and telephoto.
Your camcorder’s autoexposure system is closely analogous to autofocus: it controls an essential function that is difficult to do while shooting, it is enabled automatically when you power up your unit, and it works well much of the time.
Whether auto or manual, exposure control regulates the amount of light that strikes your camera chip. Why? Because whether you’re taping a supernova at close range or a groundhog’s back parlor, your camcorder requires exactly the same amount of light to form a good-quality image.
Your exposure system tries to deliver that just-right amount of light to the camcorder chip by changing the size of the lens opening, the amount of time allowed for recording each image (“shutter speed”), or both. As long as you stay within the camera’s limits, the auto exposure system works well.
To use it effectively, keep just one pointer in mind: when moving the camera, avoid panning across areas of different overall brightness. For example, don’t have a subject walk across a room past a background window. That will turn the subject into a silhouette and change the color of the overall shot. Instead, stage the action with the camcorder at right angles to the window, so that it never appears in the shot. If you can’t do that, break the action into two shots and edit them together to eliminate the window.
When should you use fully manual exposure? Never, perhaps, unless you have lots of experience and high-end equipment. Some camcorders allow you to lighten or darken your picture to taste while eyeballing the results on a monitor. But without that external monitor (and a good-quality one, at that) it’s very difficult to gauge the effects of exposure changes, and the results are often disappointing.
You may have great success, though, with programmed exposure settings. These settings determine lens opening, and sometimes shutter speed too. (So-called “shutter speed” is the amount of time light collects on the chip to form each image. One-sixtieth of a second is standard for NTSC format cameras; and shutter speeds range upward from there to 1/10,000 second and even higher.)
The simplest programmed setting is backlight compensation. When you pose your subject against a bright background like water, snow or sky, the auto exposure system will try to expose that bright area correctly, thereby underexposing the subject. Pressing the “backlight” button on your camcorder purposely overexposes the image somewhat, making the background too bright but the subject better exposed. More sophisticated camcorders allow you to vary the amount of over-exposure in order to compensate more precisely, while observing the effect in the viewfinder.
Programmed backlight compensation changes the amount of light admitted to the imaging chip. Other programmed exposure settings keep the brightness the same, while changing other characteristics of the image. For example, the “portrait” setting (which goes by different names and graphic symbols on different camcorders) opens up the lens iris to reduce the depth of field (focus). Using the portrait exposure setting, you can keep the subject crisp while purposely throwing a distracting background out of focus. The system does this by increasing the shutter speed to compensate for the wider lens opening.
By upping the shutter speed still further, the camcorder creates the “sports” programmed setting. This faster speed reduces the blur of fast-moving autos, skiers and the like. Some camcorders include a shutter speed so fast that it will break a golf swing into about fifteen frozen stills that you can display for analysis.
As you can see, backlight compensation settings and programmed iris/shutter combinations can allow you quite a latitude of exposure control without resorting to fully manual exposure.
Automatic White Balance
The white balance function adjusts your camcorder to the overall color cast of the light in which you’re shooting.
As you probably know by now, so-called “white” light contains a mix of colors (wavelengths) throughout the visible spectrum, from red through green and on to violet. But these wavelengths show up in different proportions at different times, giving the resulting light an overall color cast ranging from distinctly orange (candle light) to aggressively blue (a snow scene under a bright, overcast sky).
Your brain compensates for these color shifts automatically, so that whether out on the slopes or snugged before an apres ski fire, your significant other’s skin and hair appear to have about the same colors.
The white balance control is an attempt to give your camcorder a similar ability to compensate for color shifts. When white balance is working correctly, colors look identical–or at least similar–regardless of the light that’s falling on them.
Camcorder white balance systems fall into three main types: continuous automatic, switchable manual and settable manual. Here’s how each system works.
Continuous automatic white balance, as its name implies, analyzes the overall cast of the incoming light and compensates accordingly. When it works well, you could make a dolly shot from an office lit by incandescent lamps, through a showroom bathed in fluorescent light, and out into a sunny street. Analyzing and compensating on the fly, the white balance could retain consistent and pleasing colors throughout the move through three radically different flavors of “white” light.
Though many camcorders, including some mid-level models, offer only auto white balance, this system does have its drawbacks:
- The camcorder’s analysis is not always perfect, and the resulting colors are not accurate.
- The system’s ability to adjust in real time is imperfect, resulting in compensations that lag behind the shifts in color.
- The circuitry can be fooled by reflected light within the scene. For instance, suppose you have a room with light oak paneling on one wall and blue paint on the adjacent one. Depending on their locations within the room, some subjects will be bathed in warm light bounced from the oak wall, while others are washed by the much cooler light from the blue wall. Since the white balance system varies continuously, the overall color cast of the room will change unpleasantly from shot to shot.
Switchable manual white balance retains this automatic compensation as one option, but adds manual settings as well: outdoor/daylight, indoor/incandescent, and sometimes, fluorescent. With this system, you may choose automatic control, or else select a fixed color balance for the light in which you’ll be shooting.
The good news is that these preset balance settings are often better matched to actual lighting conditions than an auto system can manage. But they suffer somewhat from their one-size-fits-all design. After all, “daylight” can be as cool as a overcast summer day at high noon or as warm as a sunset through smog. A manually switchable white balance system can’t make a distinction between them.
To do that you need not a switchable manual system, but a settable one instead. In a settable system you aim the camcorder through its translucent white lens cap (or else aim it at a white card) and operate a control to set white balance precisely for that environment. The system then retains that color balance until reset.
To understand why this approach is superior, let’s return to that brown and blue room. With settable white balance, we don’t read either the warm panels or the cool paint. Instead, we read the light coming directly from the window (or the movie lights). By taking the light from its source instead of from reflecting surfaces, the white balance circuits avoid being fooled. They set white balance for the light falling on the subjects, not the light bouncing off the walls.
So when do you use manual white balance, and when do you fly on autopilot? If you’re shooting quick and dirty in a variety of locales, use your auto setting, by all means. It’s a wonderful time saver, and the results are usually acceptable.
But at other times, I always want the tightest control over color that I can get, and that means manual white balance.
Wrapping It Up
When you compare all three automatic camcorder systems, you see that you want to approach each one differently. With focus, use the automatic setting except for specific shots that it couldn’t handle.
In the case of exposure, use the auto mode judiciously. Where backlight is a problem, try to restage the shot to avoid it before enabling auto backlight compensation. In the other programmed modes, use them only for shots in which they’re essential. Sure, shoot that golf swing at 1/10,000 sec for analysis, but tape the rest of the golf game in normal exposure mode.
And for white balance? I never use automatic unless I can’t possibly help it–but then I’m something of a fanatic about that. Here I can only advise you: don’t do as I say, do as you do!