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What Exposure?

Now it’s time to take the plunge and make pictures with more control. My colleague Ralph Clevenger says, “Green means granny, and green has got to go!” On most cameras, whether point-and-shoot or DSLR, the green rectangle stands for automatic mode. Choosing green is like deferring to the expert and letting someone else decide. Sure, there are times when you’re in a pinch and you have to go with green. If you want to soar to new heights, you’re going to need to try something new.

Going Beyond Green

The four options that give you the most creative control are Manual, Aperture Value (or Aperture), Time Value (or Speed), and Program. While at first glance these options may seem confusing and abstract, they are actually quite simple. In order to chop things down for size, let’s focus on the two that will initially help you the most: Aperture Value and Time Value. First, here are a few words about exposure.

In Automatic mode, the camera determines the exposure on its own. As a result, people can typically capture properly exposed images without much thought. When using Automatic mode, you give up much of your creative control. In contrast, the more creative modes, like Aperture Value and Time Value, provide you with the means to set exposure and create a more compelling image.

What exactly is exposure? Exposure is the combination of a few factors; aperture, shutter speed, and ISO. I remember when I first heard these terms, I thought, oh no, this will never make sense. Yet, to start making great pictures, there are three basic ideas that can help: Use Aperture Value for depth-of-field (how much focus in the frame); use Time Value when you want to slow the shutter and create some blur; use ISO when the light in the scene is too dark.

Introducing Aperture

In photography, the word aperture refers to an adjustable opening that lets light flow through the lens. The size of the opening is made bigger or smaller by choosing an f-stop number. In order to understand f-stops, let’s consider a couple of simple anecdotes. The first has to do with f-stops and light; the second, with how we can begin to use f-stops for creative means.

I’ve always thought aperture and f-stop were beautiful words. But these words rarely show up in poems or songs. The exception is a great song by Jack Johnson called the “F-stop Blues.” In this song, Jack sings about the beach: “Driftwood floats, after years of erosion. Incoming tide touches roots to expose them. Quicksand steals my shoe. Clouds bring the f-stop blues.” Being a filmmaker, Jack knew about f-stops, but what’s the connection between clouds and f-stops?

This song was written while Jack was filming one of his famous surf movies. When the sky was bright, filming wasn’t a problem. Then dark storm clouds rolled in and the scene became darker and darker. He would have to choose a lower and lower f-stop number in order to let more light in. Because he was using a vintage lens when the clouds rolled in, the scene became too dark and he didn’t have any lower f-stops to choose. There wasn’t enough light to continue filming—hence the blues.

Whether you’re making a movie or capturing a still frame, f-stops work the same way. Their primary function is to control how much light flows through the lens. Thus, f-stops play an important role, both with function and form.

Aperture and Creative Control

F-stops are functional but that is not all. The f-stop number gives you the ability to control visual aesthetics. Learning how to use them well will become one of your biggest assets. To make sense of the potential creative control, let’s exaggerate things. As a people photographer, imagine that you have 25 people standing in a single-file line. You are positioned just a bit away and step to the side so that you have an angled view and can see the entire line. If you want to make a photograph with one person in focus, you choose f/1. If you want to make a photograph with all 25 in focus, you choose f/25. It’s that simple.

This anecdote is a slight exaggeration. You don’t choose your f-stop number based on the number of subjects in the frame. But conceptually this idea illustrates an immensely valuable point. The lower the f-stop number, the less in focus, or the shallower the depth of field is. The higher the number the more in focus, or the deeper the depth of field.

When you select the Aperture Value (of Aperture) mode, the camera prioritizes aperture and figures out the rest. In other words, this mode allows you to select an aperture and the camera determines which shutter speed will work best. With that in mind, let’s consider using Aperture Value in two basic photographic scenarios—portraits and landscapes.

Aperture and Shallow Depth of Field

When you are photographing people, it’s intriguing and flattering to use a low f-stop like f/2. With careful focus and composition, the result is a photograph where the eyes are sharp and the ears, hair, shoulders, and background are completely blurred. In this way, you can take creative control and choose what you want the viewer to see. Humans are attracted to areas of sharpness to help us make sense of the frame. And this doesn’t just work with people photographs but with every subject under the sun.

If you want to become an exceptional photographer, here’s what I recommend. Set your camera to the mode that prioritizes the Aperture Value (or Aperture). Choose the lowest number that is available based on your lens. Keep in mind that the lower the f-stop number, the more expensive and better the lens.

Not only does this kind of lens allow you to take pictures with less available light, the resulting images have a distinct and beautiful look that is unparalleled. While your lens might not go that low, don’t worry about it and begin with what you have. Later you will want to get something that at least goes to f/2.8 (for more on gear, see Chapter 11). For now, choose a low f-stop number, focus on specific points, and take pictures of everything you see. The results will speak for themselves.

At this juncture you may be thinking, why don’t people shoot with a shallow depth of field more often? The answer is simple. Shooting with a shallow depth of field is risky. With so little in focus it becomes incredibly easy to miss the shot. I say the risk is worth the reward. You will have to experiment with this creative technique and then decide for yourself.

Aperture and Wide Depth of Field

In 1932 photography was emerging as an art form. The medium was young and growing in many different ways. On the West Coast, soft-focused Pictoralism was starting to catch on. It was a very creative time and everything was up for grabs.

Thirty-year-old Ansel Adams and ten of his photography friends decided to take a stand. They wanted to bring more clarity to their craft, so they formed a group called f/64. Their intent was to create “pure” photography made up of sharp images and maximum depth of field. Even the group’s name comes from the aperture, which provides the widest possible depth of field on the large format camera. And thanks to the way f/64 championed the cause, photography grew and flourished in wonderful ways.

When you look at many of Adams’s landscapes, you cannot help but marvel at the composition, amazing details, texture, and sharpness throughout the entire frame. If you want to capture images with detail and sharp focus all the way through, set up your tripod and grab a wide-angle lens. Next, choose an f-stop number that is as high as f/16 or f/22. Then, position the lens and focus 1/3 of the way down the frame. This will ensure the best sharpness for the whole frame. Finally, recompose and fire away. Even if you don’t photograph landscapes, this technique works whenever you want to increase sharpness and widen depth of field.

Shutter Speed

Remember when you were a kid and you would spin in circles out in the backyard? When you spun around, the world became a blur. The spinning was disorienting, but that was what made it so fun. In photography, creating motion can make even the most ordinary scene come alive. And learning how to work with shutter speed can make photography new and fun.

When you select Time Value (sometimes called Speed), the camera prioritizes shutter speed and takes cares of the rest. In other words, you can select a shutter speed without worrying about what aperture works best. Before we discuss how to creatively begin, let’s talk about a common problem with shutter speed—camera shake.

Camera shake occurs when hand holding a camera with a low shutter speed and causing an undesirable blur in the frame. To avoid such blur, there is a general rule of thumb: Select a shutter speed that is shorter than 1/focal length. For example, if you have a 100mm lens, choose 1/100 second or faster. In this way, if you brace yourself and hold the camera steady, you will decrease the odds of a blurry frame.

Other times, while using the same lens, you will want to use blur in order to add effect. In these situations, you can choose a shutter speed slower than 1/100 and then move or zoom the camera. The actual shutter speed amount will vary depending upon the light. Experiment to determine what works best. There are a number of different types of blur you can achieve. Try the following techniques to get started: panning, spinning, and zooming.

Pan, Spin, and Zoom

Panning involves selecting a slow shutter speed and then panning the camera at the same speed as the subject. For example, if a taxi drove by you would focus and position the lens so that it always pointed directly at the car. As the camera was panning to follow the taxi’s pass, you would press the shutter and voilà, you would have an interesting frame.

Spinning involves selecting a slow shutter speed, focusing the camera, and then physically rotating the camera to pivot like the hands on a clock. To successfully execute a spin, try to think of the lens as the center axis point around which you rotate. Keep in mind that the image will be most sharp in the center, while the radial blur will gradually increase toward the edge of the frame.

To create a zoom blur, use a variable lens that allows you to quickly change the zoom amount. First, select a slow shutter speed and then focus what you see. Next, simultaneously twist the zoom control and press the shutter release. If you time it right this will create a stunning look. If you don’t happen to have a zoom lens you can accomplish the same trick. Choose a slow shutter speed and focus the scene. Next, quickly pull or move the camera backward (or forward), then back, and press the shutter release at the same time.

ISO

In certain ways, the technological advancement of digital capture has started to plateau. We now have big enough sensors to create files that are sufficient for most billboards. In more common terms, the megapixel wars are starting to wane. What was once a fistfight is now more sophisticated and subtle. Almost all cameras, even pocket cameras, have enough megapixel range. There are still other significant technological discoveries and changes. One area that has recently revolutionized how cameras are made is ISO.

ISO is a term that has been around for some time. For film and digital capture ISO refers to light sensitivity. And while film and digital capture are incredibly different, the particulars of ISO run on a parallel plane. In both cases, there is a trade-off between light sensitivity and detail. Let me explain.

A low ISO number equals a low sensitivity, while a high number equals a high sensitivity. Typically, it’s best to select the lowest ISO number possible for the scene. You will capture the highest quality frame. With film, a higher ISO results in more grain. Film grain can be appealing and can be used to create a distinct look. On the other hand, when you increase the ISO for digital capture, you’re bound to increase undesirable noise. Perhaps later, we’ll look back and nostalgically appreciate noise. For now most agree it just doesn’t have much appeal.

Higher end cameras can capture more quality at an incredibly high ISO range. And there are certain times when you’re shooting when there won’t be enough light. In those cases the only viable option will be to increase the ISO. Be sure to take some test shots and experiment with your camera to determine what constitutes an acceptable range.

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