Remembering back a few weeks ago we learned that there are three things that influence the exposure of an image in a given level of light, aperture, shutter speed, and ISO; also called the exposure triangle. This week we are going to discuss how this exposure is defined in terms of light measurement. Light measurement is obtained by a light meter which is a device built into most cameras and is designed to react to any light source it is exposed to. Your camera’s light meter will indicate whether a scene is underexposed (measurement on the minus side of the meter), overexposed (measurement on the plus side of the meter), or “properly” exposed (measurement is at 0).
As the amount of light entering the camera increases or decreases, the light meter responds by the indicator moving more towards the plus or minus side of the scale. If you recall from the exposure triangle settings, we can adjust the amount of light entering the camera by changing one or more of the three settings (aperture, shutter speed, and ISO). Once again you can practice changing these settings and see how they affect the light meter using one of the following simulators: Play by Canon, or Anderson Images.
Technically speaking, a “properly” exposed image is defined as one that is neither too dark or too light in which details are retained in both the shadows and highlights. When exposure is left for your camera to decide, like on Auto mode, it will expose for middle gray within the scene so that highlights and shadows are best preserved. Proper exposure becomes more complicated to obtain in scenes with high tonal or dynamic ranges, meaning there are a large amount of light intensities between the highlights and shadows.
When an image is “underexposed” there is too little light recorded. This is most often intentionally done to preserve a brighter background and other highlight details, producing dark and dramatic images that exhibit deepened color saturation. This technique is beneficial when trying to capture the beauty and details of the sky, especially colorful sunsets. To obtain an underexposed image light needs to be blocked from the image, aperture value can be increased (smaller opening), decreasing the shutter speed, or decreasing the ISO value.
When an image is “overexposed” there is too much light recorded. This is sometimes necessary to bring out more details in subjects that are poorly lit or against a much brighter background. When overexposure is intentionally done as a stylistic choice it produces images which are high key, light and optimistic, often having an ethereal feel. To obtain an overexposed image simply add more light to the scene, decrease the aperture value (larger opening), increase the shutter speed, or increase the ISO.
This week we are going to use intentional exposure by either overexposing or underexposing our image in order to deliberately expose creatively. The challenge is to find or create a scene having a high tonal range and creatively expose the scene by either overexposing or underexposing the image. This can most simply be accomplished by placing the subject against the sky if outdoors or against a window if shooting indoors. You may choose to underexpose the image in order to retain the details within the bright background. Or you may choose to overexpose in order to maximize details of your subject. You could also obtain large tonal range if you place your subject in a dark area and provide controlled lighting to your subject like the example image below.
You may choose to either adjust the exposure in camera making sure to pay attention to the light meter reading in order to determine if the image is underexposed (measurement towards the minus side) or overexposed (measurement towards the plus side). Or you may allow the camera to obtain “proper” exposure for you automatically (measurement at 0) and further creatively adjust the exposure in post processing. Be sure to explain your process including what type of intentional exposure you achieved, I encourage you to also include your exposure settings in your explanation.
To further depict this weeks challenge, the following image illustrates a comparison of an overexposed and underexposed landscape scene having a large tonal range and how certain details are retained in each image. You can drag the slider from side to side in order to compare details lost and retained in each image. Notice how in the left image detail is retained in the fence posts and wooded landscape but sky details are lost due to overexposure. Contrastly, the right image retains the beautiful sunset colors and cloud details in the sky but the fence posts and wooded landscape becomes dark and silhouettes as underexposed.
- Take an image that is either intentionally overexposed or underexposed (exposure can be achieved in camera or during post production)
- Post your newly taken photo during the week of Sunday, February 7 through Saturday, February 13.
- In your write up explain your process and include which type of exposure you chose and how you obtained it. I also encourage you to include your exposure settings (aperture, shutter speed, and ISO).
- Please remember to comment on at least FIVE photo submissions this week by answering the question “why?” in your comments. In other words, “why do I like (or not like) this photo?” or “why did this photo catch my eye?” Thank you!
The friendly community guidelines are pretty simple:
- Take a new photo for the current weekly theme, not something from your back catalog or someone else’s image.
- Post your photo each week to our active communities on Facebook or Flickr(or both). Tag the photo: #2021photochallenge #photochallenge #tempusaura
- Don’t leave home without your camera. Participating in the 2021 Trevor Carpenter Photo Challenge is fun and easy.