Canon EOS 60D, Let’s Get Creative

THE “SWIRLY FLASH”

It’s no secret that I don’t like to use the built-in flash. The light is harsh and flat, and when you photograph people in a dark setting, such as indoors or at night, it’s too easy to get a background that is dark and underexposed.

So when I’m in a situation in which I have no choice but to use the flash on my camera, I like to change some of the settings to give my snapshots a different look. I drag the shutter, setting it much slower than normal, usually between 1/15 and 1/4 of a second, and spin the camera on axis with the subject while the shutter is open. This keeps the person mostly frozen and well lit while creating an interesting blur of lights in the background (Figure 10.6).

By using a slow shutter speed with the built-in flash, you can create fun and unique photos of your friends.
FIGURE 10.6 By using a slow shutter speed with the built-in flash, you can create fun and unique photos of your friends.

I like to call this technique my “party trick” because when I’m in a room full of people, I’ll use this method to take a quick portrait, and often it’s something that they haven’t seen done before. This technique is not limited to DSLR cameras, and I frequently show people how to set up their point-and-shoot cameras to do it. I find that it adds a unique look to an otherwise boring snapshot. One quick tip: This type of image usually works best when there are a lot of lights behind your subject, such as the lights from a Christmas tree.

CREATING THE “SWIRLY FLASH” EFFECT

  1. Set your camera to Tv mode and start with a shutter speed somewhere between 1/15 and 1/4 of a second.
  2. Press the built-in flash button on the front of your camera.
  3. Point the camera and center your subject in the frame. Start with the camera slightly tilted, and then press the Shutter button to take a photo and spin the camera so that the subject stays centered in the image.
  4. If your flash is too bright, press the Flash Exposure Compensation button on the top of the camera and use the Quick Control dial to move the exposure value (EV) to the left. Take another photo and preview your results.
  5. If the background is too dark or too bright, you’ll want to adjust your ISO setting. The higher the ISO number is, the more ambient light you’ll bring into the background.
  6. If you have too much or too little blur in the background, adjust the shutter speed (a slower shutter speed for more blur, and a faster shutter speed for less blur).
  7. Keep adjusting the settings until you find that “sweet spot.” It will be different for each environment, and there’s no single right way to do it. Just have fun with it!

 

LIGHT PAINTING

Another fun technique that’s worth trying is light painting (Figure 10.7). For this, you’ll need a dark environment (nighttime is best), your camera on a tripod, and some semi-powerful flashlights or another light source. Shine your flashlight on your subject to light it, and in effect you’ll “paint” the light that will show up on your image. But you don’t have to paint the light on something for it to show up—if it’s dark enough you can stand in front of the camera and move the light source to make shapes or spell something out. A fun item to use for this effect is a sparkler (a type of handheld firework that emits sparkles). Just set your camera up on a tripod outdoors at night and have someone run around the frame holding a sparkler, and you’ll create shapes and streaks that can look really cool. You could also use small flashlights or LED lights. In Figure 10.8, I used a small LED flashlight with a green gel over it to add a different color to the writing.

For this photograph, I used a long exposure while my friend scribbled the haystacks with a laser pointer and I “painted” the ground with a powerful LED flashlight. I added small blue and green gels on the flashlight to add color to the image.
FIGURE 10.7 For this photograph, I used a long exposure while my friend scribbled the haystacks with a laser pointer and I “painted” the ground with a powerful LED flashlight. I added small blue and green gels on the flashlight to add color to the image.
I photographed this image with the help of my friend dav.d. That’s me writing with a small LED flashlight. The original photo was backward, so I flipped the image horizontally using editing software.
FIGURE 10.8 I photographed this image with the help of my friend dav.d. That’s me writing with a small LED flashlight. The original photo was backward, so I flipped the image horizontally using editing software.

SETTING UP YOUR CAMERA FOR LIGHT PAINTING

  1. Place your camera on a tripod in a dark environment, preferably nighttime or a darkened room.
  2. If your environment is extremely dark, set your camera to the Bulb shooting mode with a large aperture. If you have some ambient light in your scene, set your camera to Av mode and use an aperture that is large enough to capture the light from your light painting but small enough to give you a fairly slow shutter speed—several seconds is usually a good place to start.
  3. Using a cable release or one of the self-timer drive modes, press the Shutter button. If you are using Bulb mode, you’ll need a cable release in order to hold the shutter open for the duration of your light painting.
  4. With the shutter open, use a flashlight, a sparkler, or any other type of powerful light source to create your image. The creative possibilities are endless!

 

Canon 7D, Let’s Get Creative

To fi nish off this chapter, I’m going to give you a few more shooting tips, mostly fun ways you can play around with light to get some really neat results. Photography wouldn’t have as much appeal to me if it weren’t for all the exciting ways to use light, along with the different settings on my camera. These are just a few of the hundreds of ways you can experiment with your camera.

THE “SWIRLY FLASH”

It’s no secret that I don’t like to use the built-in fl ash. The light is harsh and fl at, and when you photograph people in a dark setting, such as indoors or at night, it’s too easy to get a background that is dark and underexposed.

So when I’m in a situation in which I have no choice but to use the fl ash on my camera, I like to change some of the settings to give my snapshots a different look. I drag the shutter, setting it much slower than normal, usually between 1/15 and 1/4 of a second, and spin the camera on axis with the subject while the shutter is open. This keeps the person mostly frozen and well-lit while creating an interesting blur of lights in the background (Figure 10.2).

By using a slow shutter speed with the built-in fl ash, you can create fun and unique photos of your friends.
FIGURE 10.2 By using a slow shutter speed with the built-in fl ash, you can create fun and unique photos of your friends.

I like to call this technique my “party trick” because when I’m in a room full of people, I’ll use this method to take a quick portrait, and often it’s something that they haven’t seen done before. This technique is not limited to DSLR cameras, and I frequently show people how to set up their point-and-shoot cameras to do it. I fi nd that it adds a unique look to an otherwise boring snapshot. One quick tip: This type of image usually works best when there are a lot of lights behind your subject, such as the lights from a Christmas tree.

CREATING THE “SWIRLY FLASH” EFFECT

  1. Set your camera to Tv mode and start with a shutter speed somewhere between 1/15 and 1/4 of a second.
  2. Press the built-in fl ash button on the front of your camera.
  3. Point the camera and center your subject in the frame. Start with the camera slightly tilted, and then press the Shutter button to take a photo and spin the camera so that the subject stays centered in the image.
  4. If your fl ash is too bright, press the Flash Exposure Compensation button on the top of the camera and use the Quick Control dial to move the exposure value (EV) to the left. Take another photo and preview your results.
  5. If the background is too dark or too bright, you’ll want to adjust your ISO setting. The higher the ISO number is, the more ambient light you’ll bring into the background.
  6. If you have too much or too little blur in the background, adjust the shutter speed (a slower shutter speed for more blur, and a faster shutter speed for less blur).
  7. Keep adjusting the settings until you fi nd that “sweet spot.” It will be different for each environment, and there’s no single right way to do it. Just have fun with it!

LIGHT PAINTING

Another fun technique that’s worth trying is light painting (Figure 10.3). For this, you’ll need a dark environment (nighttime is best), your camera on a tripod, and some semi-powerful fl ashlights or other light source. Shine your fl ashlight on your subject to light it, and in effect you’ll “paint” the light that will show up on your image.

But you don’t have to paint the light on something for it to show up—if it’s dark enough you can stand in front of the camera and move the light source to make shapes or spell something out. A fun item to use for this effect is a sparkler (a type of handheld fi rework that emits sparkles)—just set your camera up on a tripod outdoors at night and have someone run around the frame holding a sparkler, and you’ll create shapes and streaks that can look really cool. You could also use small fl ashlights or LED lights. In Figure 10.4 I used a small LED fl ashlight with a green gel over it to add a different color to the writing.

For this photograph, I used a long exposure while my friend scribbled the haystacks with a laser pointer and I “painted” the ground with a powerful LED fl ashlight. I added small blue and green gels on the fl ashlight to add color to the image.
FIGURE 10.3 For this photograph, I used a long exposure while my friend scribbled the haystacks with a laser pointer and I “painted” the ground with a powerful LED fl ashlight. I added small blue and green gels on the fl ashlight to add color to the image.
I photographed this image with the help of my friend dav.d. That’s me writing with a small LED fl ashlight. The original photo was backwards, so I fl ipped the image horizontally using editing software.
FIGURE 10.4 I photographed this image with the help of my friend dav.d. That’s me writing with a small LED fl ashlight. The original photo was backwards, so I fl ipped the image horizontally using editing software.

SETTING UP YOUR CAMERA FOR LIGHT PAINTING

  1. Place your camera on a tripod in a dark environment, preferably nighttime or a darkened room.
  2. If your environment is extremely dark, set your camera to the Bulb shooting mode with a large aperture. If you have some ambient light in your scene, set your camera to Av mode and use an aperture that is large enough to capture the light from your light painting but small enough to give you a fairly slow shutter speed—several seconds is usually a good place to start.
  3. Using a cable release or one of the self-timer drive modes, press the Shutter button. If you are using Bulb mode, you’ll need a cable release in order to hold the shutter open for the duration of your light painting.
  4. With the shutter open, use a fl ashlight, a sparkler, or any other type of powerful light source to create your image. The creative possibilities are endless!

HIGH DYNAMIC RANGE (HDR)

how to use HDR for landscape photography. But HDR doesn’t need to be limited to landscapes. In fact, you can photograph almost anything that is not moving and achieve some great effects. Figure 10.5 is the interior of a library photographed just before noon. The light shining through the windows added contrast to the scene, but by creating an HDR image, I was able to retain a lot of detail in both the highlight and shadow areas of the image.

This is an HDR image of the interior of a building. Notice that you can still see details in the shaded and sun-fi lled areas of the scene.
FIGURE 10.5 This is an HDR image of the interior of a building. Notice that you can still see details in the shaded and sun-fi lled areas of the scene.

 

Nikon D7000 What Is Exposure?

In order for you to get the most out of this book, I need to briefly discuss the principles of exposure. Without this basic knowledge, it will be difficult for you to move forward in improving your photography. There are many excellent books that have been written on exposure. I highly recommend Exposure: From Snapshots to Great Shots (Peachpit Press) by Jeff Revell. However, for our purposes I will just cover some
of the basics. This will give you the essential tools to make educated decisions in determining how best to photograph a subject (Figure 2.10).

This image was taken at dusk and the light was changing very quickly. I needed to adjust ISO several times to get the proper exposure.

Exposure is the process whereby the light bouncing off a subject reflects through an opening in the camera lens for a defined period of time onto the camera sensor. The combination of the lens opening, shutter speed, and sensor sensitivity is used to achieve a proper exposure value (EV) for the scene. The EV is the sum of these components necessary to properly expose a scene. A relationship exists between these factors that is sometimes referred to as the exposure triangle.

At each point of the triangle lies one of the factors of exposure:

  • ISO: Determines the sensitivity of the camera sensor. ISO stands for the International Organization for Standardization, but the acronym is used as a term to describe the sensitivity of the camera sensor to light. The higher the sensitivity, the less light is required for a good exposure. These values are a carryover from the days of traditional color and black-and-white films.
  • Aperture: Also referred to as the f-stop, this determines how much light passes through the lens at once.
  • Shutter Speed: Controls the length of time that light is allowed to hit the sensor.

Here’s how it works. The camera sensor has a level of sensitivity that is determined by the ISO setting. To get a proper exposure—not too much, not too little—the lens needs to adjust the aperture diaphragm (the size of the lens opening) to control the volume of light entering the camera. Then the shutter is opened for a relatively short period of time to allow the light to hit the sensor long enough for it to record on the sensor.

ISO numbers for the D7000 start at 100 and then double in sensitivity as you double the number. So 200 is twice as sensitive as 100. The camera can be set to use 1/2- or 1/3-stop increments, but for ISO just remember that the base numbers double: 100, 200, 400, 800, and so on. You can also use a wide variety of shutter speeds. The speeds on the D7000 range from as long as 30 seconds to as short as 1/8000 of a
second. When using the camera, you will not see the 1 over the number, so you will need to remember that anything shorter than a second will be a fraction.

Typically, you will be working with a shutter speed range from around 1/30 of a second to about 1/2000, but these numbers will change depending on your circumstances and the effect that you are trying to achieve. The lens apertures will vary slightly depending on which lens you are using. This is because different lenses have different maximum apertures. The typical apertures that are at your disposal are
f/3.5, f/4, f/4.5, f/5.6, f/6.3, f/7.1, f/8, f/9, f/10, f/11, f/13, f/14, f/16, f/18, and f/22.

When it comes to exposure, a change to any one of these factors requires changing one or more of the other two. This is referred to as reciprocal change. If you let more light in the lens by choosing a larger aperture opening, you will need to shorten the amount of time the shutter is open. If the shutter is allowed to stay open for a longer period of time, the aperture needs to be smaller to restrict the amount of light coming in.

How is exposure calculated?

We now know about the exposure triangle—ISO, shutter speeds, and aperture—so it’s time to put all three together to see how they relate to one another and how you can change them as needed.

You will hear the term stop thrown around all the time in photography. It relates back to the f-stop, which is a term used to describe the aperture opening of your lens. When you need to give some additional exposure, you might say that you are going to “add a stop.” This doesn’t just equate to the aperture; it could also be used to describe the shutter speed or even the ISO. So when your image is too light or dark or you have too much movement in your subject, you will probably be changing things by a “stop” or two.

When you point your camera at a scene, the light reflecting off your subject enters the lens and is allowed to pass through to the sensor for a period of time as dictated by the shutter speed. The amount and duration of the light needed for a proper exposure depends on how much light is being reflected and how sensitive the sensor is. To figure this out, your camera uses a built-in light meter that looks through the
lens and measures the amount of light. That level is then calculated against the sensitivity of the ISO setting and an exposure value is rendered. Here is the tricky part: There is no single way to achieve a perfect exposure because the f-stop and shutter speed can be combined in different ways to allow the same amount of exposure. See, I told you it was tricky.

Here is a list of reciprocal settings that would all produce the same exposure result. Let’s use the “sunny 16” rule, which states that, when using f/16 on a sunny day, you can use a shutter speed that is roughly equal to the ISO setting to achieve a proper exposure. For simplification purposes, we will use an ISO of 100.

Reciprocal Exposures: ISO 100

If you were to use any one of these combinations, they would each have the same result in terms of the exposure (how much light hits the camera’s sensor) but very different depth of field. Also take note that every time we cut the f-stop in half, we reciprocated by doubling our shutter speed. For those of you wondering why f/5.6 is half of f/8, it’s because those numbers are actually fractions based on the opening of
the lens in relation to its focal length. This means that a lot of math goes into merely figuring out what the total area of a lens opening is, so you just have to take it on faith that f/5.6 is half of f/8 but twice as much as f/4. A good way to remember which opening is larger is to think of your camera lens as a pipe that controls the flow of water. If you had a pipe that was 1/2 inch in diameter (f/2) and one that was 1/8 inch
(f/8), which would allow more water to flow through? It would be the 1/2-inch pipe. The same idea works here with f-stops; f/2 is a larger opening than f/4 or f/8 or f/16.

Now that we know this, we can start using this information to make intelligent choices in terms of shutter speed and f-stops. Let’s bring the third element into this by changing our ISO by one stop, from 100 to 200.

Reciprocal Exposures: ISO 200

Notice that, since we doubled the sensitivity of the sensor, we now require half as much exposure as before.

Let’s use the exposure setting of f/16 at 1/250 of a second for a sunny day for purposes of our graph. Why bother with all of these reciprocal values when this one setting will give us a properly exposed image? The answer is that the f-stop and shutter speed also control two other important aspects of our image: motion and depth of field.

Canon PowerShot G12 What Is Exposure?

In order for you to get the most out of this book, I need to briefly discuss the principles of exposure. Without this basic knowledge, it will be difficult for you to move forward in improving your photography. Granted, I could write an entire book on exposure and the photographic process—and many people have—but for our purposes I’ll just cover some of the basics. This will give you the essential tools to make educated decisions in determining how best to photograph a subject.

Exposure is the process whereby the light reflecting off a subject passes through an opening in the camera lens for a defined period of time onto the camera sensor. The combination of the lens opening, shutter speed, and sensor sensitivity is used to achieve a proper exposure value (EV) for the scene. The EV is the sum of these components necessary to properly expose a scene.

The relationship between these factors is sometimes referred to as the “Exposure Triangle,” the corners of which are made up of the following:

  • ISO: Determines the sensitivity of the camera sensor. ISO stands for the International Organization for Standardization, but the acronym is used as a term to describe the sensitivity of the camera sensor to light. The higher the sensitivity, the less light is required for a good exposure. These values are a carryover from the days of traditional color and black and white films.
  • Aperture: Also referred to as the f-stop, this determines how much light passes through the lens at once.
  • Shutter Speed: Controls the length of time that light is allowed to hit the sensor.

Here’s how it works. The camera sensor has a level of sensitivity that is determined by the ISO setting. To get a proper exposure—not too much, not too little—the lens needs to adjust the aperture diaphragm (the size of the lens opening) to control the volume of light entering the camera. Then the shutter is opened for a relatively short period of time to allow the light to hit the sensor long enough for it to record on the sensor.

ISO numbers for the G12 start at 80 and then double in sensitivity as you double the number; so, 200 is twice as sensitive as 100. The camera can be set to use 1/2- or 1/3-stop increments, but for ISO just remember that the base numbers double: 100, 200, 400, 800, and so on. There is also a wide variety of shutter speeds that you can use. The speeds on the camera range from as long as 15 seconds to as short as 1/4000 of a second. Typically, you will be working with a shutter speed range from around 1/30 of a second to about 1/2000, but these numbers will change depending on your circumstances and the effect that you are trying to achieve.

When it comes to exposure, a change to any one of these factors requires changing one or more of the other two. This is referred to as a reciprocal change. If you let more light in the lens by choosing a larger aperture opening, you will need to shorten the amount of time the shutter is open. If the shutter is allowed to stay open for a longer period of time, the aperture needs to be smaller to restrict the amount of light coming in.

How is exposure calculat ed?

We now know about the exposure triangle—ISO, shutter speeds, and aperture—so it’s time to put all three together to see how they relate to one another and how you can change them as needed.

You will hear the term stop thrown around all the time in photography. It relates back to the f-stop, which is a term used to describe the aperture opening of your lens. When you need to give some additional exposure, you might say that you are going to “add a stop.” This doesn’t just equate to the aperture; it could also be used to describe the shutter speed or even the ISO. So when your image is too light or dark or you have too much movement in your subject, you will probably be changing things by a “stop” or two.

When you point your camera at a scene, the light reflecting off your subject enters the lens and is allowed to pass through to the sensor for a period of time as dictated by the shutter speed. The amount and duration of the light needed for a proper exposure depends on how much light is being reflected and how sensitive the sensor is. To figure this out, your camera utilizes a built-in light meter that looks through the lens and measures the amount of light. That level is then calculated against the sensitivity of the ISO setting to come up with an exposure value. Here is the tricky part: There is no single way to achieve a perfect exposure, because the f-stop and shutter speed can be combined in different ways to allow the same amount of exposure. See, I told you it was tricky.

Here is a list of reciprocal settings that would all produce the same exposure result. Let’s use a traditional “sunny 16” rule, which states that, when using f/16 on a sunny day, you can use a shutter speed that is roughly equal to the ISO setting to achieve a proper exposure. For simplification purposes, we will use an ISO of 100. (I’ve included f-stops higher than f/8 to demonstrate the point, even though the G12 is capable of only f/8.)

Reciprocal Exposures: ISO 100

If you were to use any one of these combinations, they would each have the same result in terms of the exposure (i.e., how much light hits the camera’s sensor). Also take note that every time we cut the f-stop in half, we reciprocated by doubling our shutter speed. (If you’re wondering why f/8 is half of f/5.6, it’s because those numbers are actually fractions based on the opening of the lens in relation to its focal length. That’s an evasive way of saying that a lot of math goes into figuring out just what the total area of a lens opening is, so you just have to take it on faith that f/8 is half of f/5.6.) A good way to remember which opening is larger is to think of your camera lens as a pipe that controls the flow of water. If you had one pipe that was 1/2″ in diameter (f/2) and one that was 1/8″ (f/8), which would allow more water to
flow through? It would be the 1/2″ pipe. The same idea works here with the camera f-stops; f/2.8 is a larger opening than f/4 or f/8 or f/16.

Now that we know this, we can start using this information to make intelligent choices in terms of shutter speed and f-stop. Let’s bring in the third element by changing our ISO by one stop, from 100 to 200.

Reciprocal Exposures: ISO 200

Notice that, since we doubled the sensitivity of the sensor, we now require half as much exposure as before. We have also reduced our maximum aperture from f/2.8 to f/4 because the camera can’t use a shutter speed that is faster than 1/4000 of a second.

So why not just use the exposure setting of f/8 at 1/1000 of a second? Why bother with all of these reciprocal values when this one setting will give us a properly exposed image? The answer is that the f-stop and shutter speed also control two other important aspects of our image: motion and depth of field.

 

Canon EOS 60D Understanding Aperture, Shutter Speed, and ISO

Proper exposure is crucial to creating a good image, and if you’re not sure what’s going on inside the camera, it can be difficult to grasp many of the concepts you will read about in this book. Your camera can, and will, make a lot of decisions during the shooting process, and it’s important that you understand what it’s doing and why. Here I’ll cover some of the basic principles of exposure, so you have the tools to move forward and improve your photography.

Exposure is the process whereby the light reflecting off a subject reflects through an opening in the camera lens for a defined period of time onto the camera sensor. The combination of the lens opening, shutter speed, and sensor sensitivity is used to achieve a proper exposure value (EV) for the scene. The EV is the sum of the components necessary to properly expose a scene. A relationship exists between these factors that is sometimes referred to as the “exposure triangle.”

At each point of the triangle lies one of the factors of exposure:

  • ISO: Determines the sensitivity of the camera sensor. ISO stands for the International Organization for Standardization, but the acronym is used as a term to describe the sensitivity of the camera sensor to light. The higher the sensitivity, the less light is required for a good exposure. These values are a carryover from the days of traditional color and black and white films.
  • Aperture: Also referred to as the f-stop, this determines how much light passes through the lens at once.
  • Shutter speed: Controls the length of time that light is allowed to hit the sensor.

Here’s how it works. The camera sensor has a level of sensitivity that is determined by the ISO setting. To get a proper exposure—not too much, not too little—the lens needs to adjust the aperture diaphragm (the size of the lens opening; think of it as the pupil in your eye increasing and decreasing in size) to control the volume of light entering the camera. Then the shutter is opened for a relatively short period of time to allow the light to hit the sensor long enough for it to record on the sensor.

ISO numbers for the 60D start at 100 and then double in sensitivity as you double the number. So 200 is twice as sensitive as 100. The camera can be set to use 1/2- or 1/3-stop increments, but for ISO just remember that the base numbers double: 100, 200, 400, 800, and so on. There are also a wide variety of shutter speeds that you can use. The speeds on the 60D range from as long as 30 seconds to as short as 1/8000 of a second. When using the camera, you will not see the “1” over the number, so you will need to remember that anything shorter than a second will be a fraction.
Generally speaking, for handheld photography you should stay at 1/60 of a second for the slowest speed (or 1/30 if you have steady hands), so you will most likely be working with a shutter speed range from around 1/30 of a second to about 1/2000. These numbers will change depending on your circumstances and the effect that you are trying to achieve. The lens apertures will vary slightly depending on which lens you are using. This is because different lenses have different maximum apertures. The typical apertures that are at your disposal are f/4, f/5.6, f/8, f/11, f/16, and f/22.

When it comes to exposure, a change to any one of these factors requires changing one or more of the other two. This is referred to as reciprocal change. If you let more light in the lens by choosing a larger aperture opening, you will need to
shorten the amount of time the shutter is open. If the shutter is allowed to stay open for a longer period of time, the aperture needs to be smaller to restrict the amount of light coming in.

HOW IS EXPOSURE CALCULATED?

We now know about the exposure triangle—ISO, shutter speed, and aperture— so it’s time to put all three together to see how they relate to one another and how you can change them as needed.

When you point your camera at a scene, the light reflecting off your subject enters the lens and is allowed to pass through to the sensor for a period of time as dictated by the shutter speed. The amount and duration of the light needed for a proper exposure depends on how much light is being reflected and how sensitive the sensor is. To figure this out, your camera utilizes a built-in light meter that looks through the lens and measures the amount of light. That level is then calculated against the sensitivity of the ISO setting, and an exposure value is rendered. Here’s the catch: There is no single way to achieve a perfect exposure, because the f-stop and shutter speed can be combined in different ways to allow the same amount of exposure. Deciding which combination to use is one of the fun, creative aspects of being a photographer.

Here is a list of reciprocal settings that would all produce the same exposure result. Let’s use the “sunny 16” rule, which states that, when using f/16 on a sunny day, you can use a shutter speed that is roughly equal to your ISO setting to achieve a proper exposure. For simplification purposes, we will use an ISO of 100.

RECIPROCAL EXPOSURES: ISO 100

If you were to use any of these combinations, each would have the same result in terms of the exposure (that is, how much light hits the camera’s sensor). Also take note that every time we cut the f-stop in half, we reciprocated by doubling our shutter speed. For those of you wondering why f/5.6 is half of f/8, it’s because those numbers are actually fractions based on the opening of the lens in relation to its focal length. This means that a lot of math goes into figuring out just what the total area of a lens opening is, so you just have to take it on faith that f/5.6 is half of f/8 but twice as much as f/4. A good way to remember which opening is larger is to think of your camera lens as a pipe that controls the flow of water. If you had a pipe that was 1/2” in diameter (f/2) and one that was 1/8” (f/8), which would allow more water to flow through? It would be the 1/2” pipe. The same idea works here with the camera f-stops; f/2 is a larger opening than f/4 or f/8 or f/16.

Now that we know this, we can start using this information to make intelligent choices in terms of shutter speed and f-stop. Let’s bring the third element into this by changing our ISO by one stop, from 100 to 200.

RECIPROCAL EXPOSURES: ISO 200

Notice that since we doubled the sensitivity of the sensor, we now require half as much exposure as before. We have also reduced our maximum aperture from f/2 to f/2.8, because the camera can’t use a shutter speed that is faster than 1/8000 of a second.

So why not just use the exposure setting of f/16 at 1/250 of a second? Why bother with all of these reciprocal values when this one setting will give us a properly exposed image? The answer is that the f-stop and shutter speed also control two other important aspects of our image: motion and depth of field.

STOP

You will hear the term stop thrown around all the time in photography. It relates back to  the f-stop, which is a term used to describe the aperture opening of your lens. When you need to decrease the exposure, you might say that you are going to “stop down.” This doesn’t just equate to the aperture; it could also be used to describe the shutter speed or
even the ISO. So when your image is too light or dark or you have too much movement in your subject, you will probably be changing things by a stop or two.

Canon 7D Understanding Aperture, Shutter Speed, and ISO

Proper exposure is crucial to creating a good image, and if you’re not sure what’s going on inside the camera it can be diffi cult to grasp many of the concepts you will read about in this book. Your camera can, and will, make a lot of decisions during the shooting process, and it’s important that you understand what it is doing and why. Here I’ll cover some of the basic principles of exposure, so you have the tools to move forward and improve your photography.

Exposure is the process whereby the light refl ecting off a subject refl ects through an opening in the camera lens for a defi ned period of time onto the camera sensor. The combination of the lens opening, shutter speed, and sensor sensitivity is used to achieve a proper exposure value (EV) for the scene. The EV is the sum of the components necessary to properly expose a scene. A relationship exists between these factors that is sometimes referred to as the “Exposure Triangle.”

At each point of the triangle lies one of the factors of exposure:

  • ISO: Determines the sensitivity of the camera sensor. ISO stands for the International Organization for Standardization, but the acronym is used as a term to describe the sensitivity of the camera sensor to light. The higher the sensitivity, the less light is required for a good exposure. These values are a carryover from the days of traditional color and black and white fi lms.
  • Aperture: Also referred to as the f-stop, this determines how much light passes through the lens at once.
  • Shutter speed: Controls the length of time that light is allowed to hit the sensor.

Here’s how it works. The camera sensor has a level of sensitivity that is determined by the ISO setting. To get a proper exposure—not too much, not too little—the lens needs to adjust the aperture diaphragm (the size of the lens opening; think of it as the pupil in your eye increasing and decreasing in size) to control the volume of light entering the camera. Then the shutter is opened for a relatively short period of time to allow the light to hit the sensor long enough for it to record on the sensor.

ISO numbers for the 7D start at 100 and then double in sensitivity as you double the number. So 200 is twice as sensitive as 100. The camera can be set to use 1/2- or 1/3-stop increments, but for ISO just remember that the base numbers double: 100, 200, 400, 800, and so on. There are also a wide variety of shutter speeds that you can use. The speeds on the 7D range from as long as 30 seconds to as short as 1/8000 of a second. When using the camera, you will not see the “1” over the number, so you will need to remember that anything shorter than a second will be a fraction. Generally
speaking, for handheld photography you should stay at 1/60 of a second for the slowest speed (or 1/30 if you have steady hands), so you will most likely be working with a shutter speed range from around 1/30 of a second to about 1/2000. These numbers will change depending on your circumstances and the effect that you are trying to achieve. The lens apertures will vary slightly depending on which lens you are using. This is because different lenses have different maximum apertures. The typical apertures that are at your disposal are f/4, f/5.6, f/8, f/11, f/16, and f/22.

When it comes to exposure, a change to any one of these factors requires changing one or more of the other two. This is referred to as reciprocal change. If you let more light in the lens by choosing a larger aperture opening, you will need to shorten the amount of time the shutter is open. If the shutter is allowed to stay open for a longer period of time, the aperture needs to be smaller to restrict the amount of light coming in.

HOW IS EXPOSURE CALCULATED?

We now know about the exposure triangle—ISO, shutter speed, and aperture—so it’s time to put all three together to see how they relate to one another and how you can change them as needed.

When you point your camera at a scene, the light refl ecting off your subject enters the lens and is allowed to pass through to the sensor for a period of time as dictated by the shutter speed. The amount and duration of the light needed for a proper exposure depends on how much light is being refl ected and how sensitive the sensor is. To fi gure this out, your camera utilizes a built-in light meter that looks through the lens and measures the amount of light. That level is then calculated against the sensitivity of the ISO setting and an exposure value is rendered. Here’s the catch: There is no single way to achieve a perfect exposure because the f-stop and shutter speed can be combined in different ways to allow the same amount of exposure. Deciding which combination to use is one of the fun, creative parts of being a photographer.

Here is a list of reciprocal settings that would all produce the same exposure result. Let’s use the “sunny 16” rule, which states that, when using f/16 on a sunny day, you can use a shutter speed that is roughly equal to your ISO setting to achieve a proper exposure. For simplifi cation purposes, we will use an ISO of 100.

RECIPROCAL EXPOSURES

If you were to use any one of these combinations, they would each have the same result in terms of the exposure (that is, how much light hits the camera’s sensor). Also take note that every time we cut the f-stop in half, we reciprocated by doubling our shutter speed. For those of you wondering why f/5.6 is half of f/8, it’s because those numbers are actually fractions based on the opening of the lens in relation to its focal length. This means that a lot of math goes into fi guring out just what the total area of a lens opening is, so you just have to take it on faith that f/5.6 is half of f/8 but twice as much as f/4. A good way to remember which opening is larger is to think of your camera lens as a pipe that controls the fl ow of water. If you had a pipe that was 1/2” in diameter (f/2) and one that was 1/8” (f/8), which would allow more
water to fl ow through? It would be the 1/2” pipe. The same idea works here with the camera f-stops; f/2 is a larger opening than f/4 or f/8 or f/16.

Now that we know this, we can start using this information to make intelligent choices in terms of shutter speed and f-stop. Let’s bring the third element into this by changing our ISO by one stop, from 100 to 200.

RECIPROCAL EXPOSURES: ISO 200

Notice that, since we doubled the sensitivity of the sensor, we now require half as much exposure as before. We have also reduced our maximum aperture from f/2 to f/2.8 because the camera can’t use a shutter speed that is faster than 1/8000 of a second.

So why not just use the exposure setting of f/16 at 1/250 of a second? Why bother with all of these reciprocal values when this one setting will give us a properly exposed image? The answer is that the f-stop and shutter speed also control two other important aspects of our image: motion and depth of fi eld.

STOP

You will hear the term stop thrown around all the time in photography. It relates back to the f-stop, which is a term used to describe the aperture opening of your lens. When you need to decrease the exposure, you might say that you are going to “stop down.” This doesn’t just equate to the aperture; it could also be used to describe the shutter speed or even the ISO. So when your image is too light or dark or you have too much movement in your subject, you will probably be changing things by a stop or two.