Sunday, October 11, 2009

Show Me The Light!
Understanding Your ISO

One of the great advancements in the conversion from film to digital photography is the ability to change the ISO, or film speed, with any picture. With film, photographers were stuck with an ISO, or ASA, for 12, 24, or 36 exposures. Today, a camera's sensitivity to light can be changed with push of a few buttons, allowing advantages that previous photographers could only dream of.

ISO, or International Standard Organization, is a group of people that get together to determine the standard measurements for the world. For photography, they determined what qualified any certain film's sensitivity to light and gave it a numerical value. Most 35mm photographers used 100, 200, or 400. Here in America, we have our own "standard" as well, ASA, or American Standard Association, so you may of heard film called "100ASA." Digital cameras are sold all over the world, that's why ISO is used instead of ASA.

For photographers, changing the ISO setting on your camera allows you change the camera's sensitivity to light. In lower light, you can turn the flash off and shoot in existing light by raising the camera's ISO number. Auto ISO usually defaults to a lower number and the camera fires the flash. With the flash intentionally turned off, and the ISO number set higher, you will have the ability to take pictures indoors, given there's enough light to get a fast enough shutter speed for a correct exposure.

When a camera is set to program, usually labeled with a P, the camera reads the light and sets the f/stop and shutter speed. This is point-and-shoot at it's best. Sometimes, the camera may fire the flash when natural light would actually look better. The camera may also choose a shutter speed that is too slow to be handheld for a clear picture, or too slow to capture the action. Now that we have the capability to change the ISO easily, we can adjust the ISO to a higher number, making the camera more sensitive to the light. As previously stated: If there's enough light available, with the camera set to a higher ISO, you can turn off the flash and shoot with available light. In addition, raising the ISO will also force the camera to use a faster shutter speed, which may be fast enough now to handhold the camera or stop the action your trying to capture.

So what's the catch? Noise. We called it film grain when we shot 35mm: As the ISO number goes up, photos become more and more "grainy." Digital noise equals tiny bits of misinformation that get in the way of the overall clarity of the photo. As the ISO is raised, our photos don't look as sharp, crisp, or clean because of the noise. I think it's a worthwhile trade-off when trying to shoot candid, nothing kills candid photography like a flash going off, and the artificial quality of flash photography can be unflattering at best.

It's time to experiment: This will work best if you're in your living room, or inside somewhere.

  • Grab your camera and set it to P for Program, (which is different than the green "auto" setting that won't let you override any features.) Some cameras have a red camera icon that stands for program, just in case your camera doesn't have a "P" mode.
  • Take a picture of your computer screen or tv from at least five feet away.
  • Now look for the flash icon; it looks like a lightning bolt with an arrow at the bottom. If it's not an obvious button, try looking on or around the toggle switch, (the up/down/left/right control switch.) Once you find it, push it a few times until you see the symbol for "no flash," a circle with a line through the lightning bolt.
  • Take another picture of your computer screen from the same spot as the first one.
  • Now it's time to change your ISO. You may find the letters ISO somewhere on or around your toggle switch, or by a button. (If you own a Canon, you may need to, depending on the model, push the FUNC (function,) button to activate a short menu selection on the left side of your screen. Toggle down to ISO for the different choices.) If it's not accessible on the outside of your camera, push the menu button and start toggling through the different choices, until you find ISO. Most cameras will have it labeled ISO, some call it Sensitivity.
  • Start with the lowest number, usually 100, and take a picture from that same spot as above.
  • Go back into your ISO and go up one level, 200. Take another picture, same spot.
  • Go back into your ISO and proceed with a picture at every ISO number.
Now take a look at the shots. Push playback, usually a blue triangle. You should see quite a difference in the exposure, from dark and maybe blurry to bright and clear. You can also zoom into your photo by the the usual zoom button and scroll around the picture using the toggle switch. If you press DISP, you might be able to see the different f/stops and shutter speeds, depending on your camera model. Don't worry for now if the color looks yellow or off, we'll cover that it the future.

Well, this has been quite a bit of info, so in the next installment we'll start looking at the different preset camera settings such as portrait, landscape, sport, and night shots. Until then, practice and take a lot of pictures. Experiment. There is no combination of buttons you can push on your camera that will make it explode.

Friday, October 9, 2009

Exposure 101: Part 3
The Aperture and Shutter Speed

The art of photography comes in the balance of light and time. The magical box that allows us to record history, a moment in time, with the mere push of a button is an amazing achievement. The camera in your hands can create images that also convey an emotion, perspective, inspiration, fascination, the list goes on. Gone are the days of worrying about running out of film. You have 24 rolls of film now, and it's reusable. Push the button. You have a rechargeable battery. Push the button.

So, a camera has an aperture in the lens that lets in different amounts light and controls if the background is blurred or clear. The camera also has a shutter that blocks the light until the button is pushed. The shutter controls how long the light passing through the lens will be allowed onto a sensor: the faster the movement, the faster the shutter speed needs to be to freeze the action. The combination of how much light, (aperture,) and amount of time, (shutter speed,) create an exposure.

A "correct" exposure means that the balance between aperture and shutter speed leaves your subject not too bright, nor too dark. If your subject is too bright, or overexposed, then too much light was coming through the aperture or the shutter speed was too long. Conversely, if your subject is too dark, or underexposed, then the aperture didn't let enough light through or the shutter speed was too fast.

For most photography exposures, as more light is allowed through the aperture, a faster shutter speed will be needed to balance the exposure. If less light is allowed through the aperture, (a higher f/stop number,) then a slower shutter speed will be needed for balance. If a faster shutter speed is desired, then the camera will need to open up the aperture, (lower f/stop number.) If a slower shutter speed is used, then the camera will need to close down the aperture, (higher f/stop number,) for balance. Simply stated, as one number goes up, the other must come down.

Keep in mind that when you are looking at the shutter speed on your camera, it might read, for example, 1/60 or just 60, but they both mean 1/60th of a second. As we start exploring the different functions and settings on your camera, what you choose to tell the camera what you're taking a picture of is going to affect either the shutter speed or the aperture. There are no extra components that a "professional photographer" has on their camera that you don't have, except for more shutter speeds and f/stops available to choose from. Shutter speed and f/stop, that's it. But there is another aspect in photography that can affect the f/stop and shutter speed, the film speed or "ISO."

In our next installment, we will see how the ability to change the camera's sensitivity to light, or ISO, with every picture has dramatically changed the world of photography with digital cameras. We will also start digging in to the automatic settings on your camera to see how they will affect the f/stop and shutter speeds for different types of pictures.

Thursday, October 8, 2009

Exposure 101: Part 2
The Shutter Speed

In the last installment, we looked at the functions of the aperture or f/stop. Now we can look at the second half of how a camera takes a picture: the shutter speed.

The shutter inside your camera blocks the light that is coming through the lens from reaching the camera's sensor. Think of it like mini-blinds on a window that won't allow any light through from outside. You are the "sensor" inside the house. When you push the button to take a picture, the shutter, opens and allows the light to pass through the lens and onto the sensor. The time it takes for the shutter to open and close is called the shutter speed. Shutter speeds can vary from hours to a fraction of a second. In fact, most photography is shot between 1/30th and 1/250th of a second.

The faster the shutter opens and closes, the more ability you have to stop, or freeze action. If movement is occurring in your shot, and a slower shutter speed is used, the movement will be recorded as blur. There is a point, usually anything slower than 1/30th of a second, when the shutter speed is too slow to handhold the camera and still get a clear picture, so the camera must be put on a tripod. Using a tripod allows you to shoot with slow shutter speeds because you have removed yourself, and any movement, from the camera when it's taking the picture.

Let's look at an example. You are at a sporting event, and just took some pictures. Reviewing your pictures, you notice that a picture is blurred even though you know the camera focused properly: The shutter speed was too slow to handhold the camera steady enough for a clear picture, or you moved while the picture was being taken. The next picture you look at has clear mountains, trees, people on the sideline, but the players on the field are blurred: The shutter speed was fast enough to hold the camera steady, but the shutter speed was too slow to stop the action.

Have you ever cut, gutted, and masterfully carved a fantastic jack-o-lantern for Halloween only to have your flash fire for the picture and ruin all the ambiance? How about that Christmas tree that looked so magical to your eye? This year is going to be different. Your camera needs to be held steady with image stabilization, or put on a tripod, with a slower shutter speed and the flash turned off to capture the lighting correctly. The only thing universal with cameras anymore is the tripod mount, (the hole where you screw the tripod into the camera,) so any tripod will work.

If you don't own a tripod yet, and you're considering getting one, I've recommended 2 compact tripods in the sidebar to the right; the mini-spider is tiny, so it will fit in your camera bag but it can't hold a larger point-and-shoot camera. The gorillapod is larger but more versatile because you can wrap the legs around a pole, tree branch, or your car window, and it can hold a larger camera too. A tripod opens-up a whole new world of photography, done at slower shutter speeds. With a little practice, you'll be ready for the holidays this year, and get the shots you want.

When you get a chance, get your camera out and push half-way down on the picture button, (also known as the shutter release,) until it focuses in front of you, and check to see if your camera displays the shutter speed and f/stop. If not, you can try pushing the display button, labeled DISP, a few times to change the different information displayed on the screen.

In the next installment, we will explore the balancing act between the shutter-speed and the f/stop. It's a dance of time and light that come together to form a memory.

Many thanks to all who have responded so positively to this new project.

Stay tuned, we're almost through the meat-and-potatoes, and then it's on to dessert!

Wednesday, October 7, 2009

Exposure 101: Part 1
The Aperture (or f/stop)

Before we dive straight into the features and functions of your camera, we need to lay the groundwork of how a camera takes a picture. Every camera has 2 components that create the picture: the aperture (or f/stop) and the shutter speed. Understanding how these 2 components work together will help you to use the features of your camera, which will help you to get the shot you want. Let's start with the functions of the aperture.

The aperture is a hole in your lens that controls two aspects: 1. How much light is coming through the lens, and 2. How clear the focus will be before and after your subject.

The first aspect is fairly straightforward: The lower the number, the more light you're letting come through the lens. Think of the aperture like the pupil of your eye. A low number f/stop, (i.e. f/2.8) lets more light through the lens, a dilated pupil, than any higher f/stop number. As the f/stop number goes up, less and less light is allowed through the lens, a small pupil.

The second aspect is more about creative control. Though the camera will focus on the subject to make it clear, the aperture controls what else in the entire scene will be clear or blurred-out. A low number f/stop will blur the foreground and background. As the f/stop number increases, the amount of clarity before and after your subject will increase as well. In photography, this amount of clarity is referred to as depth-of-field. Low number f/stops will blur the background, (shallow depth-of-field.) Maximum depth-of-field is achieved at the highest f/stop number of your camera. All the f/stops between the minimum and maximum will give you varying degrees of clarity throughout your photograph.

Keep in mind that changing the f/stop will control the amount of light through the lens and the amount of depth-of-field at the same time. Low number f/stops let in more light and have shallow depth-of-field. Higher f/stop numbers let in less light and have more depth-of-field.

The aperture is one half of how your camera takes a picture. Check back soon for the next installment: the Shutter Speed!

Learn How To Use Your Point-and-Shoot Camera

Greetings Fellow Photographers

To fulfill the request of a friend, and for the benefit of anyone who enjoys photography, I will be posting a beginning course for digital point-and-shoot cameras. Having a compact camera with you, and knowing how to use it, can lead to a lifetime of fantastic memories through pictures. Stay tuned as we explore the features and functions of your camera that will transform your shapshots into works of art, (or at least the picture you were trying to get in the first place.)