The Exposure Triangle

The Exposure Triangle

Photography is fun, rewarding and sometimes a time consuming experience! Capturing the perfect shot, whether its portraits, landscapes, or creative shots like high speed photography (lightning, etc.), can allow a person to flex their skills. Pictures like these can be enhanced by taking a few minutes to understand your camera and lens operations which will greatly improve your photography skills and pictures.

Learning your DSLR camera features can sometimes be a little daunting. In this article, we hope to explain in a few words a summary of the most important features in getting the right exposure.

There are three main elements that exists on any DSLR camera, Aperture, Shutter, and ISO. Understanding how these work and using them together will allow you to be more creative that using the standard “auto” setting on your camera.

The Aperture controls the size of the opening in your lens and is denoted as f/2.8, f/4 and so on. The higher the number, the smaller the opening and thus less light is let in.

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Knowing how to use the f-number is helpful in controlling the depth-of-field or in other words, the often desired, background blur. We’ll get to more of that in later on. Note: f-number ranges are determined by the lens and not the camera.

The Shutter controls the amount of time light is let in. Numbers are in seconds for example, 0.3” 1/4”, 1/125”, 1/1000”, etc. Slower shutter speeds allow more light in and increases motion blur. Faster speeds such as 1/250”, 1/500” and higher are “stop-action” settings. Shutter speeds lower than 1/8”, 1/4”, etc. will require a very steady hand or a tripod.

Finally, another setting that’s helpful to understand is the ISO. The ISO represents the sensitivity towards the light. Low ISO numbers are often more desired because they are less noisy and provide sharper detail. Images with high ISO tend to be more grainy especially in the dark or black areas of the photograph.

These three elements make up the Exposure Triangle, knowing how these three elements depend on each other will help immensely.

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Tip

Each full stop of the aperture either doubles or halves the size of the lens opening (depending which direction you’re adjusting). In order to get the same exposure, the shutter needs to adjust for the lens opening. The table below illustrates the aperture and shutter combinations to achieve the same exposure. Think of it this way, if you double the size of the opening (each f/stop to the left on the table), the shutter speed has to double as well.

Remember, the smaller f-number represents a wider opening in the lens and thus more light is let in. The way to counteract it is to increase the shutter speed or increase the ISO. Each element is codependent on the other.