It’s time for a new technical challenge this week and we have made it all the way to the third and final member of the exposure triangle. To recap we have had challenges on the Exposure Triangle, Intentional Exposure, Creative Shutter Speed, and Creative Aperature. This week we are going take images using either a very low or a very high ISO to learn how this setting can effect exposure. If you recall from the Exposure Triangle challenge, ISO refers to how sensitive the camera’s sensor is to light. A low ISO (smaller number) is less sensitive to light and will produce a darker image. While a high ISO is more sensitive to light and will result in a brighter image. So by adjusting ISO you are adjusting the sensitivity of the camera’s sensor to the light.
Unfortunately there is a trade off with higher ISO settings. The higher the ISO setting the more grain or noise is also introduced to the image. Essentially the image becomes more “rough” and loses its smooth deep-blacks and crisp-clean whites as illustrated in the image below, “Love Remains”. The level of ISO and amount of noise introduced is dependent on the quality of each camera’s sensor. Some cameras will start producing noise at ISO levels around 1000 and others not until 10,000! Sometimes photographers will shoot at high ISO levels solely just to introduce noise for artistic expression.
So the challenge this week is going to involve manually setting your aperture and shutter speed and adjusting the ISO levels to obtain the desired exposure under different lighting situations. I have broken the challenge into two different lighting scenarios in which you can choose one for your image this week.
Challenge option 1: Low ISO (200 or less) in bright outdoor lighting. Start by choosing a subject outdoors in bright light. Some ideas would be landscape such as a sunrise or a flowing waterfall, or an outdoor portrait of your favorite person or pet. Next set your aperture at or smaller than f/8 (f/8.0, f/11, f/16, etc) so that you have a large dof (which is great for landscape photography). Adjust your shutter speed at or less than 1/200. Lastly adjust your ISO, these two settings are going to let a lot of that bright light into the camera’s sensor, so in order to make the sensor less sensitive to all of the light, it is necessary to set a low ISO to achieve proper exposure.
Challenge option 2: High ISO (800 or greater) in low outdoor (evening) or indoor light. For this option choose to shoot in low light such as early evening outdoors or anytime indoors. Subject matter is open, but something that is stationary or moving very slowly (if you want more of a challenge) is ideal. Set your camera aperture larger that f/8 (f/5.6, f/4.0, f/2.0 etc.). Adjust the shutter speed at or greater than 1/100. Lastly adjust your ISO, these settings in a the low light situation are going to reduce the amount of light entering your camera’s sensor and therefore a higher ISO setting will need to be used in order to increase the sensitivity of the sensor to light and obtain proper exposure.
One thing to keep in mind is that the slower your shutter speed, especially less than 1/100, the more camera shake becomes an issue. Depending on your lighting situation, subject matter, and aperture setting you may need to use a tripod to prevent a blurry image.
The Challenge Summary
- Take an image of your choice using one of the above options of either a very low or a very high ISO.
- Post your newly taken photo during the week of Sunday, September 12 through Saturday, September 18.
- In your write up explain which option, high or low ISO, you chose and your individual lighting situation. Also include your camera settings (aperture, shutter speed, and ISO).
- Please remember to comment on at lease FIVE photo submission 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.