One of the most important yet intimidating skills of photography is correctly achieving exposure. “Correct” exposure involves a combination of many elements and can be both technical as well as artistic and therefore is often left for the camera to decide automatically. Whether the photographer allows the camera to decide on the exposure or chooses to set it themselves, it is always achieved by three key factors: aperture, shutter speed, and ISO- thus referred to as the exposure triangle.
Aperture refers to the size of the opening at the end of the lens and allows a certain amount of light to enter that opening and expose the sensor (like opening the shades of a window a little or a lot to control the amount of light that enters the room). Aperture settings are recorded as a fraction called f-stops such as f/4, f/5.6, etc. The “f” value of the f-stop is the focal length of the lens and the fraction value determines the size of the opening. For example, if the focal length of the lens is 50mm and the f-stop is f/2, then the opening of the aperture is 50mm/2 which equates to a 25mm opening of the aperture. Therefore a larger aperture setting of f/8 for example would allow a 50mm/8 or a 6.25mm opening which is much smaller than the previous example and would result in less light entering the lens and thus produce a darker image.
Shutter speed contributes to exposure by controlling how long the light is able to enter and expose the sensor. Shutter speed is also recorded as a fraction in terms of seconds, 1/60s, 1/125s, 1/250s, etc. Simply the longer the shutter is open, the more time light is allowed to enter and expose the sensor which results in a brighter image.
The third player in the exposure triangle is ISO. ISO refers to how sensitive the camera sensor is to light. A lower ISO, around 200 is less sensitive to light and will produce a darker image. As the ISO is increased the sensor becomes more sensitive to light thus resulting in a brighter image.
As this is just an introduction to the exposure triangle, there will be more details of these settings in future challenges. This week we are just going to focus on familiarizing ourselves with the exposure settings of our images. But if you are interested in experimenting with the exposure triangle and want to view the effects each one has on an image, there are a few camera simulator labs that you can practice with such as Play by Canon or Exposure Simulator. You can read more on the Adorama website.
For this week your challenge is to photograph any image of your choice using any exposure mode of your choice (automatic or manual). Obtain the exposure settings used and include the aperture, shutter speed, and ISO of your posted image in your write up. I further challenge you to choose an image that depicts the type of photography that interests you. We each have an individual story that explains how, why, or what has encouraged us to want to photograph. Maybe you like capturing candid everyday life stories or maybe you prefer special moments; you may be more drawn to landscape photography or are interested in portraits. Whatever your story is, try to exemplify that in your submitted image and then provide a brief description of how your image relates to your photographic interest.
- Take one image of your choice, preferably depicting your photographic interest or style.
- Post your newly taken photo during the week of Sunday, January 17 through Saturday, January 23.
- In your write up include the exposure triangle settings (aperture, shutter speed, and ISO) as well as brief bio or description of your photographic story and how it is depicted in your submitted image.
- 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.