Getting Creative with Exposure Modes
On today’s cameras, point-and-shoot photography usually gives you quite decent results despite having become a truly simple process. But advanced exposure modes, used together with a smartly-chosen amount of exposure correction, can help you go yet another step beyond that. Let’s take a look at how.
Most DSLRs and high-end compacts have several advanced, non-fully-automatic exposure modes. These modes let you influence one out of the three fundamental exposure parameters: sensitivity, shutter, and speed. Exposure correction, meanwhile, can be found on perhaps every digital camera today.
If you own a DSLR or an advanced digital compact, then your mode dial probably contains the standard symbols used for these modes—P, A, S, M (Nikon and most other brands) or P, Tv, Av, M (Canon).
Full Automatic: Great for Beginners
Full automatic exposure mode is typically marked with a green camera icon, arrow, or rectangle, or just the word “Auto.” With this mode on, it is not possible to set the shutter size and speed, and usually the sensitivity is set automatically as well. Just a few things can be adjusted in this mode. Usually this short list includes flash, JPEG quality, and the self-timer. Some digital compacts don’t have an advanced exposure mode. On these, an automatic mode with a broad range of settings is the most creative mode left available.
But it’s not all bad, because this mode is actually ideal for point-and-shoot photography. The programs for automatically calculating exposure in modern cameras are now sophisticated enough that picture quality when using them is not a problem.
These exposure programs’ default settings preserve the ratio between shutter size, shutter speed, and sensitivity, to minimize the chance of blurring. In low-light situations, they use a minimal f-stop and raise sensitivity while retaining an exposure time of at least 1/50 s. In most cases they also use a flash too, and that’s one exception to the rule of modern automatic exposure generally being good enough—there are some low-light situations where a flash is a bad idea. For example, when taking pictures of buildings, the exposure program pointlessly uses the flash because it has detected low light levels.
There are digital compacts with what are called automatic scene modes; these are also fully automatic, but with a preference for some parameters over others. Typical examples include a sports or kids mode with a quick shutter speed, a landscape mode with a higher aperture value, or long exposures for night scenes. All of these definitely are worth the trouble—they can give you visibly better results than the generic automatic mode.
This is quite similar to full automatic, but leaves you more room to alter the camera settings, so you can choose a focus point, exposure measurement mode, sensitivity, white balance, etc. Usually named the “P” or “AE” program. Most cameras offer very convenient adjustment of exposure values, that is, changes to the shutter speed/f-stop combination that leave exposure the same. You can influence a photo somewhat by experimenting with these combinations—by your choice of speed or aperture.
This is one of the most frequently used exposure programs, especially on DSLRs, where it helps beginners better understand the principles behind photography, and also offers a certain amount of room for creative photography.
Shutter Priority, Aperture Priority: For Advanced Users
This pair of modes automatically calculates one point of the speed-aperture-sensitivity triangle to ensure a good exposure. For shutter priority (Tv or S), you choose a speed and other values, and then the program calculates an appropriate aperture value based on your choice and on the current lighting conditions and exposure measurement setting.
It’s useful in every situation where you need control over exposure time—for sports events and anything else with fast-moving objects, but also for slow-moving objects like flowing water. In dim lighting conditions, you can also minimize blurring by setting an appropriate speed and aperture.
If you ever sneak a peek at the settings on a pro photographer’s camera, you’ll probably find them using aperture priority (A, Av). That’s because this mode helps them work with depth of focus and thus with the picture’s overall feel. Also, most lenses get their best results with a medium aperture—another reason to use the mode.
Manual Settings And Exposure Correction
Manual mode is the very opposite of full automatic: the aperture, speed, and all other settings are fully in your hands. While manual mode is priceless for experienced photographers, it’s closer to worthless for normal users, for whom the need to constantly set exposure is frustrating. However, there are still cases where manual mode is a good mode for anyone, such as night sky exposures that need a very long exposure time.
Unlike the other modes, manual mode does not offer exposure correction. Exposure correction pushes a picture towards a darker or brighter look, or more precisely, it can correct for naturally occurring errors in the automatic mode (e.g. the mode is “confused” by a snow-covered plain).
Exposure correction, or “compensation,” is measured in units called EV (exposure value). Compacts range from +3 to -3 EV, while DSLRs range from +5 to -5. Increasing correction brightens a picture, while decreasing correction darkens it—in other words, the correction deliberately slightly overexposes/underposes it. A tried-and-true rule says that it’s better to have a slightly underexposed picture than an overexposed one, since overexposed areas are always white, and moreover digital cameras capture a wider range of tones in the shadows than in the lights.
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