So, you’ve taken the leap and joined the ranks of the photography community.
Aside from your excitement about your new hobby, you find that when you read articles or participate in forum postings about photography, there’s some terms you just don’t understand.
That can be frustrating, for sure, but this guide to basic photography terms will get you in the know!
Exposure, Underexposure, and Overexposure
The term “exposure” has a couple of different meanings.
First, it refers to exposing an image. In the film days, this meant exposing a frame of film to light. Nowadays, it refers to exposing your camera’s digital sensor to light.
Second, this term refers to the level of brightness or darkness of an image.
If an image is too dark, it’s underexposed because there wasn’t enough light. The image above appears to be underexposed for this very reason.
If an image is too bright, it’s overexposed because there was too much light. The image above is overexposed due to the abundance of light and relatively little dark values.
However, what constitutes an overexposed or an underexposed image is in the eye of the beholder because both can be used as a creative mechanism. In fact, both images above were likely exposed as they were on purpose to achieve the dark and light looks, respectively.
The level of exposure is controlled by three factors: aperture, shutter speed, and ISO (discussed below).
You can also impact the level of exposure via exposure bracketing and exposure compensation. For detailed discussions of each, check the learn more section below.
Aperture, Shutter Speed, and ISO
The basic exposure settings on your camera control various aspects of light.
Aperture refers to the size of the opening in the lens, and it controls the amount of light.
A good analogy for aperture is a window – the larger the window, the more light that’s allowed into a room. Conversely, the smaller the window, the less light that’s allowed in. Aperture works in the same manner.
As shown above, the aperture is measured in f-stops, where a small f-stop represents a large aperture, and a large f-stop represents a small aperture.
For example, f/2.8 is a very large aperture where f/22 is a very small aperture.
Aperture doesn’t just affect the exposure, though. The size of the aperture also impacts depth of field (discussed in more detail below).
Large apertures, like f/2.8, create a shallow depth of field in which the background is nicely blurred (i.e. as is usually found in portraits).
Conversely, small apertures, like f/22, create a large depth of field in which everything from foreground to background is in focus (i.e. as is typical of landscapes).
Shutter speed refers to the time it takes the camera’s shutter to open and close, and is therefore responsible for the
of light hitting your camera’s sensor.
Shutter speed is measured in fractions of a second, like 1/50 or 1/200, as well as whole seconds, like 1 or 2.
Naturally, the longer that the shutter remains open, the more light that’s able to reach the sensor.
But when considering shutter speed, also consider that it’s responsible for how motion appears in the shot.
A fast shutter speed will freeze motion, assuming the shutter speed you select is appropriately fast enough for the subject. For example, to freeze the motion of the runner shown above, a shutter speed of 1/500 seconds is more than sufficient. But to freeze the motion of a cheetah running, a much faster shutter speed – like 1/4000 seconds, would be more appropriate.
The opposite is true – a slow shutter speed will blur movement, with increasingly slow shutter speeds resulting in blurrier movement effects, as seen in the cityscape above.
The final component of exposure is ISO.
ISO controls the sensitivity of your camera’s sensor to light.
A low ISO number, like 50 or 100, indicates very little light sensitivity. Conversely, a high ISO number, like 3200 or 6400, indicates much more sensitivity to light.
Additionally, ISO controls the appearance of digital noise or grain in your photos.
The higher the ISO, the more visible digital noise becomes. That means if you want a “cleaner” look, use a low ISO. If you want a grainy look, use a higher ISO.
Get a detailed overview of aperture, shutter speed, and ISO in the video above by Adorama and Mark Wallace.
Depth of Field
Depth of field can be defined as the area of an image that’s in sharp focus.
In the image above, we would describe the depth of field as quite large, as everything from foreground to background is in focus.
As noted earlier, the aperture you use determines the depth of field, with a large aperture producing a small depth of field and a small aperture producing a large depth of field as seen above.
But aperture is just one factor in determining the depth of field. Also influencing depth of field are:
- The distance between the camera and the subject – The closer you are to the subject, the shallower the depth of field.
- The distance between the subject and the background – The further away the subject is from the background, the shallower the depth of field.
- Focal length – All else being equal, the longer the lens, the shallower the depth of field.
- Sensor size – All else being equal, the larger the sensor, the shallower the depth of field.
As mentioned above, a shallow depth of field is often used in portraiture because the blurry background helps set the subject apart. However, landscapes tend to benefit from a large depth of field so viewers can get a clear, sharp view of the entirety of the scene.
Get a quick visual overview of depth of field in the video above by Advancing Your Photography.
Most beginning photographers rely on their camera’s LCD to inspect an image for the quality of exposure.
However, this isn’t the best way to determine if you’ve gotten a good mixture of light and dark pixels…
Your camera’s histogram is a graphic representation of light values, from dark to midtones to light, as seen in the images above.
Typically, you want a chart that peaks in the middle, like a traditional bell curve, as this indicates that the image has strong midrange values, and some light and dark values as well. See a histogram and learn about its usefulness in the video below by Tony and Chelsea Northrup.
If the chart peaks on the left, that indicates that there’s too many dark values. If it peaks on the right, the opposite is true – there’s too many light values in the shot.
Because the histogram doesn’t depend on the quality of the LCD, it’s a much more precise measure of the exposure of an image.
Metering refers to the act of measuring the light in a scene to determine the exposure.
Essentially, metering works off middle gray to determine if an image is overexposed or underexposed. That means that if there is an abundance of dark or light values in the scene, your camera might be tricked into thinking that the scene is brighter or darker than it actually is.
If you shoot in full auto mode, metering is done on your behalf by the camera, and that’s where mistakes in measuring the light tend to occur.
However, you can take control of metering and use one of several metering modes (matrix, center-weighted, spot, or partial) to measure the light more accurately. Get a detailed explanation of metering in the video below by PhotoRec TV:
These metering modes differ in their name from one manufacturer to the next but basically perform the same function regardless of name. Here’s a quick summary of how each metering mode works:
- Matrix metering means the camera reads the light from various points throughout the scene. That means it takes all areas of the shot into account when determining the available light.
- Center-weighted metering looks only at the light in the middle of the frame. This is advantageous when your subject is also in the middle of the frame.
- Spot and partial metering are closely related, and only take a very small portion of the scene into account when determining the light that’s available. These modes are advantageous in situations in which backlighting is an issue.
Putting It All Together
This is by no means a comprehensive list of every photography term you need to know…
However, these are some of the most essential concepts with which you need to be familiar in order to take your photography to the next level.
Consult the detailed guides I’ve linked to in the “learn more” sections above, and you’ll be well on your way to developing a stronger understanding of these concepts.
In the meantime, learn a little more about these terms, put these concepts into practice, and watch as the quality of your photos improves!