Exposure

A good exposure is about balance between the light and dark tones of a photograph.

It is a successful combination of ISO, Shutter-Speed and Aperture, so that we are looking at an image which is pleasing to the eye. Much like successfully combining all the necessary ingredients to make a bread or pizza dough.

At present, a smartphone's default app does not allow the user access to any of the camera's real settings. Third-party apps (free and paid) gives us the ability to adjust the ISO and Shutter-Speed, while the camera sets the remaining property (Aperture) for us.

This is known as a Shutter-Priority mode and it is very popular in cameras.

My DSLR (Digital Single-lens-Reflex) gives me an automatic mode, a Shutter-Priority mode, an Aperture-Priority mode and also full-manual control, where I get to set everything myselfBeing in full-manual is where the fun is, and these are the steps I generally take to establish a balanced exposure formula...

1. First, I set the ISO, thus establishing the sensitivity of my exposure. Setting the ISO first is a holdover from film days when we put a roll in the camera, then turned a dial to physically set the ISO.

2. Next, I pick the property, either the Shutter-Speed or the Aperture, which creatively holds the greatest impact for my photograph. If I am shooting a waterfall, my intention is either to blur the water or capture it in motion, so Shutter-Speed is what I will set next. If I am photographing a person and want to blur the background, I may want to set the Aperture after the ISO. 

3. I now set the remaining property to whatever brings my light-meter (next page) into balance.

4. I take a photograph and look at the results.


That's it. That's my process, a simple 1-2-3 workflow.

Establish the sensitivity, select the property that holds the greatest creative value, then balance it out by setting the remaining property.

This exposure formula is not set in stone, not by a long shot. 

Rarely do we nail the exposure the very first time, sometimes it may take a little tweaking. Also, within any given exposure formula, there is a wide latitude of options to choose from...

ISO 200 | 0.5 seconds | f/29

ISO 200 | 0.5 seconds | f/29

Every single image in this slideshow has the same tonal balance, - meaning one image is not really any lighter, nor is it any darker than the others, aside from the variable of shooting in natural light.

They all look different visually from one image to the next, but tone-wise, they are the same.

Examine each photograph's individual exposure formula listed on the lower-left of the slideshow box and we begin to see how the 3 properties interact with each other. 

The ISO remains constant at 200, but the Shutter-Speed and Aperture values change from one image to the next, in order to maintain our tonal balance.

If there is a relatively long-duration Shutter-Speed, then I must equally close down the Aperture to reduce the light-strength passing through the lens.

If, on the other hand, I want a faster Shutter-Speed to freeze the water in action, I would open the Aperture up to allow the most light to pass through and set the fastest Shutter-Speed available.

The duration of time our film/sensor is being exposed to light will have a dramatic impact on a photograph, so have fun experimenting with your options!

For these photographs, I was in Shutter-Priority mode.

I ran through the entire course of Shutter-Speed settings available to me based on ISO 200. As I adjusted the Shutter-Speed, the camera adjusted the Aperture. (Actually, there were more photographs taken, but I thought I'd limit it to 15 for this example).

This is a perfect illustration of what is meant by maintaining balance.

As long as I arrive at an exposure formula that best matches the photograph in my imagination, it doesn't matter how I get there. As I like to say: “There’s more than one way to grandma’s house.”

As a matter of personal preference, I often find myself in the Aperture-Priority mode or in full-manual. In any of the priority-modes, I will make sure the camera isn't setting the last remaining property to something that causes a problem for my image.

This graphic represents the "Exposure Triangle."

A good, balanced exposure means we have control over 2 of the 3 sides of this triangle, otherwise we are not in control and our exposure will probably suffer. Simple as that.

In daylight, this is easy to control as there is usually plenty of light.

If hand-holding a camera in low-light conditions though, we may find ourselves out of our depth if we don't have a tripod or some other means to securely keep our camera still during the long Shutter-Speeds. Even with cranking up the ISO and opening the Aperture as wide as it can go, we may still be dealing with a Shutter-Speed that simply cannot be handheld.

Many times, we find ourselves simply unable to photograph the moment. That's when we have to just enjoy it and take the photograph with our imagination. I often find myself using such exercises, imagining which exposure formula would work best in a given situation, and you should, too.

"To photograph is to hold one's breath, when all faculties converge to capture fleeting reality. It's at that precise moment that mastering an image becomes a great physical and intellectual joy."

Henri Cartier-Bresson

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