Many people who go out and buy a camera think that once they do, all their images will be professional by putting the camera on the “P” mode or one of the settings that describes what they want to do. In reality, those don’t give you professional images and instead give you a programmed decision determined by your camera maker. Worse, from image to image, there isn’t any consistency in the lighting at the same location because each image is re-evaluated based on what it sees at the time with the camera’s sensor. I also hear from some people that they never use automatic modes – yet when I see their flash settings, their flash is in fully automatic so they are shooting in fully automatic when they shoot with a flash.
Why is all of this important?
In order to capture an image the way you see it, you have to understand how the camera sees that same image in order to capture what you see and not what the program says it sees. To do this, you must understand the “exposure triangle”.
You probably have heard of the “exposure triangle” and I am sure many can Google and see what it is if you haven’t. There are three things in this triangle: ISO, aperture, and shutter speed. Each time one is doubled, it is called “1 stop” of light. Each time one is halved, it is called “1 stop” of light. So, if you increase one of them by 1 stop and decrease another by 1 stop, you have the same exposure. Depending on which you choose, you can change certain things about your image that you capture.
Let’s start with the first: ISO. ISO is how you change your light sensitivity. A low ISO isn’t very sensitive and a high ISO is very sensitive. A typical low ISO is 100. A typical high ISO is 6400. “What kind of trade offs do I have to worry about?” you ask. The higher the ISO, the more noise there is in the image you capture. This is significantly noticeable the older your digital camera is. If you are one of the few who are shooting film, then you will notice this as “grain” with the consumer grades of film showing more than the pro grades of film. You need to practice at different ISO settings so you know what you will get for noise with your camera. With film, you practice with one type for a while and you will become familiar with the noise it has over time, but practice will help.
The next one is aperture. This is the lens opening on your camera and describes how “open” it is to let light in. A wide aperture lets in a lot of light (usually F2.8 or wider). A small aperture lets in very little light (usually F16 or F32). Again, there are trade offs on a scale to using either end of these. This is called “depth of field” and describes how much is in focus in your image. It is called depth because it describes a distance from the front of your focus to the back of your focus giving you a distance that will be in focus (if your subject is in that range, it will be in focus; outside of that range, it will be out of focus). On film cameras, you probably have this showing on your lens in the form of multiple colours or a chart on the zoom lens itself. If you shoot at F32 (a very small aperture), then everything will be in focus (most everything depending on the focal length of your lens and the distance to your subject, but that is for another blog post). As we move to the other extreme, F2.8 (a very wide aperture), the amount that stays in focus is a lot less as the depth of field is smaller. Have you ever wondered how someone takes a picture and the background is completely fuzzy but the subject is in focus? The person taking it shot it with a wide aperture. You may hear others refer to the blur caused as “bokeh” (pronounced “bo-kah” or “bo-kay”). Bokeh refers to how the blur occurs – soft and smooth is often better than sharp and quick that depends on how the aperture is made. There are a complete style of images where this is used with bright lights that are out of focus in the background and conforms to the shape of the aperture.
The last part is shutter speed. This is how long the camera is open to accept light. A slow aperture lets lots of light in and motion blur. A fast shutter speed requires a lot more light and can freeze the fastest motion. A fast shutter speed is 1/2000 of a second. A slow shutter speed is 1 second. A lot can happen in one second that won’t happen at 1/2000 of a second. Most people learn this intuitively because of camera shake. When you hand hold a camera, there is a safe speed that won’t have camera shake and anything slower it does. For the typical person, this is the inverse of the camera focal length at any ISO (and called the “inverse focal length rule”). The rule says that your shutter speed should be 1/(focal length) or higher to avoid camera shake. For example, if you are shooting at a 50mm focal length, your shutter speed should be 1/50 second or faster to avoid camera shake. Another example, you are shooting at 250mm focal length so your shutter speed should be 1/250 second or faster to avoid camera shake.
Getting used to this exposure triangle is key to capturing the images you see, and can only be done by not shooting in automatic modes. Start by using either shutter or aperture priority and then moving to fully automatic. You will see your photography improve a lot when you do. You will also see a greater consistency in the images that you do take.