Basics in Photography

// Photographers

November 30th, 2010

The concept behind it all

The shutter speed controls the length of time that light is allowed into the camera. The slower the shutter speed, the more time that the shutter is open and the more light that is let in. The faster the shutter speed, the less time that the shutter is open and the less light that is let in.

The aperture is the volume of light that is allowed in while the shutter is open. The bigger the aperture, the more light that is let in. The smaller the aperture, the less light that is let in.

The ISO relates to the sensitivity of the camera and how easily it will capture the light. The more sensitive your camera, the more light that is captured. The less sensitive your camera, the less light that is captured.

To simplify the explanations even further, imagine water flowing through a pipe. The pipe represents your camera and the water represents the light going into your camera. Using this illustration, the shutter speed would equate to how long the pipe stays open. The longer that it’s open, the more water that can pass through. Similarly, the aperture would equate to the width of the pipe. The wider the pipe, the more water that can pass through. The ISO is a bit different and has nothing to do with the pipe. Instead, let’s imagine that the ISO relates to the bucket at the end of the pipe that is taking the water. If you have a large bucket, you would be able to hold more water. If you have a small bucket, your capacity to hold water would be limited. This is the same as the ISO on a camera. A high ISO is the same as the big bucket, allowing you to capture more light in one go, whereas a low ISO is the opposite.

Canon 550D control dial

These days, most cameras (if not all) have a program mode that automatically takes care of these functions for you, adjusting them according to the amount of light available at any given time. In which case, you might ask why you need to know about these functions. There are occasions when this automatic feature gets it wrong and exposes the photo incorrectly. It might be because there is strong light coming through a window behind your subject (known as backlight) causing your photo to look darker than it should or because you want to change the settings for effect so that the background behind your subject is blurred (known as a shallow depth of field). Whatever the reason, if you can grasp the concept of these functions in your camera, you will be better prepared to shot in conditions or for effects that program mode cannot handle.

While it’s important to know what each of these functions do and how they will effect your photo, it’s also important to know the side effects that each can have. If you were to shoot on a slower shutter speed to get more light from a dark setting, you increase the chance of movement in the photo because you allow the camera more time to see the movement. If you increase the aperture, you increase the blur in the background and foreground of your photo. If you increase the ISO, you increase the “noise” in the photo (noise refers to the degradation of image quality, often seen as a grainy effect in a photo). So while each of these functions can help in low light conditions, they also bring their own effect to the photo. Some of these effects may be desired, while others may not. Either way, it’s important to know what these effects are so that you can find the balance between light, effect and quality in your photo.

The examples above will give you an idea of what the effects look like when dealing with large apertures, slow shutter speeds and high ISO. The first photo was taken during the reception of a wedding and shot using a slow shutter speed (0.6 secs) to capture light in a dark setting. You will notice a ghosting effect as the wait staff move through the room while the photo is being taken. The second photo was taken with a larger aperture (f2.8). You will notice the blur effect. The groom’s eye is in focus, yet the tip of his nose and more noticeably his ear is blurred. The third photo was taken at an extremely high ISO setting (ISO 25,600). This was because there was minimal light, with only a light above the front entrance, above the side window, internal lighting from the building and a distant light out of frame providing the only light source. The photo would have been greatly underexposed at a lower ISO setting. The result, more light but with a grainy effect to the photo.

Putting it into practice

Together, the exposure, aperture and ISO control the amount of light processed by the camera and the subsequent exposure of the photograph. Make sense? Well, perhaps not to someone who is new to photography or their camera. It can take a while to get comfortable with these three areas, especially all at the same time. So what should you do? If you are totally new to photography or your camera, we suggest leaving your camera on auto or program mode and concentrating on the subject in your photo. Let the camera worry about the exposure. Once you’re comfortable with the auto or program mode on your camera you can start taking control of it so that the camera does what you want it to. The best place to start is with the aperture priority mode (represented on your camera by AV). This mode allows you to concentrate on just the aperture setting and the camera takes care of the rest for you. You set the aperture and the camera calculates the shutter speed based on the available light and current ISO. By only having to adjust one thing (aperture) and not three (aperture, shutter speed and ISO), you can concentrate on the subject that you are about to photograph and let the camera do the rest for you. Likewise, the shutter speed priority mode (represented on your camera by TV) will provide you with the same level of automation. Instead of setting the aperture, you set the shutter speed and the camera calculates the shutter speed for you.

Before jumping into manual mode (represented on your camera by M) where you can control both aperture and shutter speed, it is worthwhile familiarising yourself with the ISO on your camera. Set the aperture (if in aperture priority mode) or shutter speed (if in shutter speed priority mode) and take a photo. Change only the ISO to something else and take another photo. Notice what happens. To get the same exposure, the shutter speed changes (when in aperture priority mode) or the aperture changes (when in shutter speed priority mode) to adapt to the different light sensitivity of the camera. This is the camera automatically adjusting for you.

Now, flick over to manual mode and the camera stops the automation and allows you to control everything. This can seem daunting at first, but with a little practice and lots of photos later (some good and some not so good), you will soon become comfortable with having total control and wonder how you ever shot in program or semi-program mode before. The benefit of the manual mode is that you can ensure that the exposure is exactly how you want it. The program and semi-program modes don’t always get it right.

To summarise all of that, the best way to get comfortable with your camera and find the setting that best suits you is to try them all, take as many photos as you can, test the different modes in different lighting conditions and see which one you prefer. There is nothing wrong with staying with a program or semi-program mode. It’s all about personal preference and the environment that you are in. If you shoot in manual mode, you may find times when it’s best to change to a program mode so you can concentrate on other aspects of the photograph. Likewise, if you shoot in a program mode, you may one day have the need to go manual because the camera simply isn’t doing what you need. For what it’s worth, there are professional photographers who shoot daily in (full auto) program mode. They say the ‘P’ stands for Professional Mode and not Program Mode. With the exceptional photos that some of them produce, who am I to argue.