Back to Basics Photography: Exposure Control

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Back to Basics Photography: Exposure Control

photography lesson on exposure control

Back to Basics Photography: Exposure Control

In the upcoming months John J. Pacetti, CPP, AFP, will be writing a series of basic photography lessons.  To find them all just search “Back to Basics” on our blog. This is the first article in this series.

John is a frequent visitor to the MCP Facebook Community Group. Make sure to join – it’s free and has so much great information.

What is exposure control?

The better you expose and set up the image when you record it, the less work you have to do later when you process it.  I would rather spend all that time in editing, in other ways.  If I’m constantly editing because “I can fix it later,” I’m not using my valuable time to my advantage.  If I capture the image properly in camera, I can spend that valuable time, with my family, on a hobby (oh, wait photography is my hobby).  You get what I mean.

Exposure control is the use of shutter speed (SS), F-Stop (F-#), ISO to capture a properly exposed image. You are controlling the amount of light and length of time that light is hitting the sensor.

A quick explanation:

  1. Shutter Speed – Duration the shutter is open.  The length of time the shutter is open allowing light to the sensor.
  2. F-Stop/Aperture – The opening in the lens.  The size of the opening that light passes through to the sensor.
  3. ISO – The sensitivity of the sensor to light.  Lower ISO for bright scenes, higher ISO for low or poor light scenes.

The below center images is an example of a good exposure.  A good exposure can be achieved with any setting combination of ISO, F-Stop and Shutter Speed.

Under exposed 2 Stops:

Good Exposure:


Over exposed 2 Stops:

How it works:

ISO, F-Stop or Shutter Speed all interact with each other.  You can’t change one without changing another and maintain the same exposure.  That being said, assume you have set your proper exposure. You decide to make and adjustment in your F-Stop.  You need to change either your SS or ISO (maybe both) in order to maintain the same good exposure.  So, in order to maintain the same good exposure, If you change ISO; you need to change either F-Stop or SS. If you change SS; you need to change either F-Stop or ISO.  If you change F-Stop; you need to change either SS or ISO.

To give you an idea of what I’m talking about, go get your camera, I’ll wait………………………… Now, look through your view finder.  At the bottom of the view finder (at least in my Canon Cameras, that’s where it is) there is an exposure meter.    Whatever your settings are, for this experiment, almost don’t matter.  If you change your shutter speed, you’ll notice the pointer in the meter move left or right depending on if you increase or decrease your SS.   The same thing will happen if you change your F-Stop.  You are changing the exposure setting and can see that effect on the image exposure by the movement of the pointer on the exposure meter.  This is a simple demonstration of course, but should give you some idea how exposure control can be effected for changes in any one of the the parts of the exposure triangle, SS, F-Stop and ISO.

I hope this gives you a general understand of ISO, F-Stop and Shutter.  We’ll explore this more as our series continues.


John J. Pacetti, CPP, AFP   –   South Street Studios  –

2013 Instructor at MARS School- Photography 101, The Basics of Photography

If you have question, feel free to contact me at  This email goes to my phone so am able to answer quickly.  I’ll be glad to help in any way I can.

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  1. December 8, 2012 at 2:34 pm —

    C-41 film has great exposure latitude. I’ve read Kodak’s Tech Pubs on their C-41 film portfolio and none mention pushing or pulling development or the ISO range of their films.
    I’ve exposed their C-41 B&W film, Kodak BW400CN rated at ISO 400, from ISO 100 (accidentally) to ISO 1600 (intentionally) with great results.
    Kodak’s Tech Pubs for their traditional B&W film, TMAX and Tri-X, do mention push and pull development. I’ve sent TMAX 3200 pushed 2 stops to 12800 to a B&W lab for development. There was one photo where the grain exploded, but other photos were acceptable because of the rock concert lighting conditions.

  2. December 8, 2012 at 2:21 pm —

    Great explanation about the exposure triangle.

    I normally leave my camera on auto, usually [P] instead of [Av] or [Tv], but I will use the exposure compensation dial to underexpose or overexpose up to +/- 2 stops in 1/3 increments. I will shift from Program to Aperture-priority or Shutter-priority depending on what I want to get.

    I do have a project of photographing the Full Moons where I will use total manual control using the “Sunny F/16 Rule”.

  3. December 5, 2012 at 11:22 am —

    Great basic explanation, John. Looking forward to the rest of your series.

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Back to Basics Photography: Exposure Control