Here we have an interesting variety of images captured by using a slower shutter speed.
In the first image, a slower shutter speed is employed in order to capture the moment of a weightlifter at work, with the motion blur enhancing the effect of the physical action. In the second image, the chaos of lottery balls in motion and colliding with each within a container is achieved by using a much slower shutter speed, an aesthetic effect that could not be achieved if a faster shutter speed were used. The last photo is a particularly interesting example not only in that it’s a night photo, but that streaks of light coming from the stars in the night sky are captured as the earth rotates. Given the light and the photographer’s desired effect, only by using an extremely slow shutter speed (much slower than our chart even displays) could this image be captured in such a way.
When shooting with slower shutter speeds, it’s often advisable to use either a tripod or a stationary surface on which to mount your camera in order to reduce undesired or superfluous blur in your images. Doing so will stabilize both the camera and the image itself.
It’s also important to note here that there are two different types of blur that occur with slow shutter speeds: motion blur and camera shake. Motion blur occurs when the subject being photographed is moving in front of the camera; this is the type of blur that can be either captured or reduced depending on the shutter speed, even within a slower range of speed.
Camera shake, however, refers to movement captured due to the camera itself moving while the shutter is open. This “shake” or blur is often undesirable, and once again can be eliminated most effectively by using a tripod or another stable surface (as opposed to holding the camera in your hands).
Balancing the Exposure Triangle
In our previous installment, Understanding Aperture: Controlling Light Based on the Exposure Triangle, we took an in-depth look at a variety of different ways that proper light exposure can be achieved by adjusting the camera’s aperture. This time, let’s consider some examples of how this balance can be achieved in relation to shutter speed. But first, let’s briefly summarize what we’ve learned about fast shutter speeds versus slow shutter speeds.
Fast shutter speed:
- Freezes subjects in motion (eliminates blur)
- Allows for less light to reach the camera sensor
- Is best employed in settings with abundant light
Slow shutter speed:
- Captures subjects in motion (allows blur)
- Allows for more light to reach the camera sensor
- Is best employed in settings with limited or low light
Now, we know that shutter speed is equivalent to the time interval during which the camera’s shutter is open. This is one part of the exposure triangle. As a reminder, the other two aspects of the triangle are aperture and ISO.
A Note on Aperture
Aperture, as discussed in the previously mentioned guide, is the variable size of the opening in the lens when an image is being captured. Aperture not only controls how much light enters the camera, but also determines the depth of field of an image.
Briefly stated, a wider aperture allows a great deal of light to reach the camera sensor, but will result in a shallow depth of field. A shallow depth of field basically means that areas of the image that are farther away from the photographer will appear blurry, while subjects or objects nearer to the camera will appear crisp and focused.
The opposite is true for a narrower (more closed) aperture, in which less light will reach the camera sensor, but will provide a wider depth of field. A wider (deeper) depth of field will keep all areas of the image in focus regardless of their relative distance away from the photographer.
A Note on ISO
ISO (to be discussed in detail in an upcoming guide) refers to a camera’s relative sensitivity to light, or, in other words, its “ability” to capture light.
So, let’s use an example to demonstrate how we might “balance the triangle” under a particular circumstance.
Imagine you have a subject you wish to photograph and you adjust your aperture to a wider setting, which provides you with a great deal of light. However, it also provides a shallow depth of field, and you’re not content with this as you wish for a greater area of the image to remain in focus.
You then adjust to a narrower aperture setting, which corrects your problem regarding the depth of field and image clarity. Yet again, your image now appears far too dark for your liking, and another adjustment needs to be made. But what do you adjust?
You remember that a slower shutter speed allows for more light to reach the camera sensor, so you adjust the speed down the scale to a longer exposure time. But in doing so, you’re also reminded that this allows for greater motion blur, and, in this case, that simply won’t do.
You want to eliminate that undesired motion blur, so you adjust back to a faster shutter speed so that you can freeze your subject in time. But now the image is back to being a bit too dark. So what now? Are you stuck?
Not at all. This is where you turn to the third and final part of the exposure triangle, the ISO. At this point, you’ve achieved both a satisfactory depth of field and your desired lack of motion, but you still need more light. The solution here is to raise the ISO to a higher setting in order to increase the camera’s light sensitivity, thus achieving a brighter exposure proper to your chosen subject.
To illustrate this adjustment, below is an example of an image noticeably improved in quality by increasing the ISO level by multiple intervals:
Working with adjustments in shutter speed can be one of the most enjoyable aspects of learning to master manual photography, as it allows for an incredibly wide variety of photographic effects and offers a vast array of aesthetic and stylistic choices and variations. As we like to remind you, experimenting with the settings on your camera – shutter speed included – is part of the joy of learning photography; there is always more to learn and the journey is half the fun. So as you continue to explore and develop your craft, make sure to remind yourself to have fun and keep an open mind.
Thank you for reading, and keep an eye out for our forthcoming guide on the third part of the exposure triangle: ISO.