“Understanding Exposure” by Bryan Peterson – Exercise 1: the photographic triangle

Shutter speed: 1/6 Aperture: F/16

I finally opened Bryan Peterson’s Understanding Exposure (3rd edition) and after digesting the first 40 pages, those technical terms of shutter speed, aperture, and exposure are becoming de-mystified and less confusing. To help you solidify this vague concept of “exposure” Robertson suggests taking out your camera to take some photos with different exposures, and jotting down each photo’s camera settings.
For my first exercise, I am focusing on what Peterson refers to as “The Photographic Triangle”: APERTURE, SHUTTER SPEED, and ISO.

I have only taken one photography class in my life, from my local YMCA in Port Angeles, WA and although I did gain some tips that improved my shots I still had not grasped these technical photography terms. Because of that I still have not been totally comfortable shooting in Manual mode. From reading Robertson’s book I picked up a few tips that are starting to shed some light on these confusing terms; these are not all quotes from Robertson’s book…mostly they are my paraphrasings:

  • “The smaller the f-stop number, the larger the lens opening; the larger the f-stop number, the smaller the lens opening.”
  • “Aperture refers to the lens opening so for example, F/22 or F32 is a small aperture.”
  • “When you change your aperture, remember to check your shutter speed and adjust it using your light meter”
  • “Exposure time= shutter speed”

Still confused? Yeah, I don’t have it down 100% yet either. Let’s forget all this blabbidy-blah. Let’s take a look at some photos! 🙂

Below are photos which illustrate some of what I learned about the Photographic Triangle. The caption under each photo shows my camera settings. To keep it simple, each photo was shot with ISO-200 and WB Cloudy so really I am focusing on how the shutter speed and aperture settings affect each photo. The photos were untouched aside from being compressed to 72dpi. The concept of composition is also touched upon a bit, since concepts such as depth of field can affect your composition, or how well you can create a storytelling portrait. That’s all I’ll mention about that though since I’ll save that for another post.

I hope sharing my step-by-step exercises with you as I go through Robertson’s excellent book help you become more comfortable shooting in the Manual mode.


I needed a subject and I decided Nora’s dirty feet would do. I shot these while in our apartment in Santiago, Chile. It is absolutely impossible to keep her feet clean here, especially since she loves to run around barefoot on our balcony.

In this exercise I am trying different exposures and compositions to make Nora’s feet look dirty but to also tell a story. What is more effective? When the feet are isolated, showing Nora’s legs, showing Nora’s face/eyes in the background, with a short or long depth of field (eg. background clear or blurry), showing only her soles or with the pink toes peeking out?

I spent about 20 minutes taking these photos and found that reviewing the photos and documenting what shutter speed and aperture I used for each photo is really helping me understand exposure and composition.

Remember, only the shutter speed and aperture were changed in these photos. ISO-200 and WB Cloudy were used for all of them.

2B Shutter speed:1/8, Aperture:F/16

2A Shutter speed:1/80, Aperture:F/5.6

3A - Shutter speed: 1/800 Aperture: F/1.4

3B - Shutter speed: 1/1250 Aperture: F/1.4

3C - Shutter speed: 1/1600 Aperture: F/1.4

Can you see how the shutter speed affected the lighting of the photo? For example, in 3A and 3B I think the feet look dirtier when I used a longer shutter speed (eg bigger number). And, how the aperture (eg. F-stop) of F/1.4 in photos 3a,b,c and 4a made the background look blurrier, giving it a shallower depth of field? By blurring the background your eyes can more focus on the feet. And, lastly, there’s a difference in composition since different elements of Nora’s feet, legs and face are visible in the photos.

1A - Shutter speed: 1/60 Aperture: F/5 (sofa visible in background)

1B - Shutter speed: 1/60 Aperture: F/5 (adjusted for composition)

This was an effective exercise for me. If you are a kinesthetic learner like me (eg. you learn by doing), actually taking the photos yourself, rather than reading a book or looking at someone else’s photos, will really help you grasp these concepts. I’m still learning so I’ll keep taking photos, reading Bryan Robertson’s book, and share what I learn with you!

Now, get out your camera and take your own photos! Come back and post your photos and your blog link and share them with me! 🙂


3 comments on ““Understanding Exposure” by Bryan Peterson – Exercise 1: the photographic triangle

  1. […] been awhile since I posted results from one of my photography exercises using Bryan Peterson’s “Understanding Exposure” book. I had two goals in mind when employing two of Bryan Peterson’s […]


  2. MKA says:

    Dear Amelia,
    What awesome picture you have here. I’ve got D5000 Nikon and just starting to learn something. Looking forward to learn something from you.


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