Aperture priority on your EOS camera
Aperture priority is the ideal mode for shooting portraits like this.

The Mode Dial on your EOS camera is divided into two sections: the Basic Zone and the Creative Zone. On most models this distinction is only made in the instruction manual, but in recent models like the Canon 700D / T5i (shown below) it is also marked on the Mode Dial:

The EOS 700D/T5i mode dial
The Creative Zone modes on the EOS 700D / T5i are separated from the Basic Zone modes by a white dividing line.

The Basic Zone

The Basic Zone includes all the camera’s fully automatic exposure modes, including Scene Intelligent Auto, Creative Auto, Portrait and Landscape. They are aimed at photographers who don’t know which settings to use themselves. If you want to take a landscape photo, yet haven’t used a digital SLR before, it is much quicker to go to Landscape mode than it is to learn what the camera settings are for.

The drawback of Basic Zone modes is that the camera is making all the creative decisions for you, including file format (JPEG, not Raw), Picture Style, ISO, aperture and shutter speed. That’s a great help if you really know very little about photography, but also very restrictive.

[REWIND: I Just Bought a New DSLR Camera, Now What? A Basic Primer on Automated Camera Modes]

Note that some cameras, such as the Canon 5D Mark III, don’t have a Basic Zone on the mode dial, as Canon assumes that photographers buying these more advanced models only want to work within the Creative Zone.

The Creative Zone

The Creative Zone is where photographers who want to control their camera and select which settings to use themselves go. You can set everything yourself, from white balance to Picture Style to file format.

There are four Creative Zone exposure modes: Program Auto Exposure (P), Aperture Priority (Av), Shutter Priority (Tv) and Manual (M). Today we’re going to take a close look at Aperture Priority.

Aperture priority on your EOS camera
Aperture Priority is an ideal mode for taking portraits. In this example, I set the aperture to f2 to take advantage of the beautiful bokeh produced by my Canon 85mm lens.

Aperture Priority

In the wonderful world of the world wide web, some photography writers seem to take pleasure in propagating ill-thought out homilies. One of these is that you should use Manual mode all the time. While there are many good reasons to use Manual mode (I’ll explore some in a future article) to suggest that it is the only mode you should use is nonsense. There are times when an automatic mode, such as Aperture Priority, is the best choice.

In Aperture Priority mode, you set the aperture and ISO values, and the camera sets the shutter speed according to the reading from its built-in exposure meter. Unlike Basic Zone modes, you retain full control over every other camera setting.

Here are some situations when using Aperture Priority mode may be the best option:

1. When the aperture setting is more important than shutter speed and ISO. For example, you may be shooting a portrait at a wide aperture to blur the background. Or you may be taking a landscape photo and require a small aperture to get the entire scene in focus. In both situations, you prioritize the aperture setting and then adjust the ISO and shutter speed to suit.

2. The light is changing. You may be in a situation where you are moving from sun to shade, the sun might be going in and out behind the clouds, or the light may be fading at the end of the day. In each case, using an automatic exposure mode like Aperture Priority means the camera adjusts to the changing light. Set the ISO and aperture, and let the camera set the shutter speed. You can control the shutter speed indirectly by changing the ISO value.

3. You need to react quickly to a changing situation. If you are shooting street photography, or an event or festival, or even a news event, you need to be able to react quickly when something interesting happens or the moment may be lost forever. If you are in Manual mode, then it takes too long to alter the settings. In an automatic mode, the camera reacts for you.

Aperture priority on your EOS camera
Aperture Priority is also idea for landscape photography. Set a low ISO, an aperture that is small enough to render the entire scene sharply (f8 in this example) and let the camera set the appropriate shutter speed. You will need a tripod to support the camera if you’re working in low light.

Exposure Compensation

Another benefit of using Aperture Priority is that you can easily make adjustments to the exposure settings using exposure compensation. For example, if you are photographing a light toned subject, then you know the camera will underexpose the image. It is easy to make an adjustment by setting exposure compensation to +1 or +2 stops, then confirm you are correct by looking at the histogram.

Understanding EOS

Understanding EOS ebookAndrew S. Gibson is the author of Understanding EOS: A Beginner’s Guide to Canon EOS Cameras. The ebook covers both technical and creative aspects of photography to enable you to use your EOS camera better.