Photography 101: Aperture, Shutter Speed, ISO and the Art of Getting the Shot

 

Photography 101:
Aperture, Shutter Speed,
ISO and the Art of
Getting the Shot

Article researched and compiled

by Michael A. Buccilli

There is a moment that happens to almost every beginning photographer.

You pick up a camera, look at the buttons, dials, numbers, symbols, and menu options, and suddenly something that should feel creative begins to look suspiciously like an engineering exam.

Aperture. Shutter speed. ISO. F-stops. Exposure compensation.

It can become complicated very quickly.

But photography becomes much easier to understand when we stop thinking about those settings as technical obstacles and start looking at them for what they really are: tools that help us decide how we want a photograph to look.

Photography is not about memorizing every setting on a camera. It is about noticing something worth photographing and then making a few choices that help the camera capture what you saw.

That is where aperture, shutter speed, and ISO come in.

Together, photographers often refer to them as the exposure triangle. Aperture and shutter speed directly control how much light reaches the camera sensor, while ISO helps determine how the camera renders the brightness of the captured image.

More importantly, each one also changes the appearance of a photograph in its own way.

Understanding those differences is one of the first steps toward moving from simply taking pictures to deliberately creating photographs.

And that is where the fun begins.

First, Everything Starts With Light

Before getting into camera settings, there is one thing worth remembering:

Photography begins with light.

Every photograph is created because light enters the camera and reaches the sensor.

The camera does not see a landscape, a person, a bird, or a city street quite the same way we do. It records the light reflected from those things.

Morning sunlight washing across a stone building.

Golden light catching the tops of autumn trees.

A reflection dancing across Lake Erie.

A neon sign glowing against a rainy sidewalk.

All of those scenes are ultimately collections of light.

Aperture, shutter speed, and ISO give photographers different ways to work with that light.

We will eventually explore light itself in another Photography 101 article because understanding light is one of the most fascinating parts of photography.

For now, think of light as the raw material.

The camera settings are the tools we use to shape what becomes the photograph.

Caption:

Light and movement can completely transform
an everyday scene. Here, sunlight catching the
breaking waves helped turn afamiliar shoreline 
moment into something more dramatic.

Photo copyright:

Michael A. Buccilli 

That photograph is a good example of why photography begins before the shutter button is pressed.

The water was already there. The reeds were already there. The sunlight was already there.

The photograph came from noticing what those elements were doing together.

Aperture: What Do You Want the

Viewer to Notice?

Inside a camera lens is an opening called the aperture.

The aperture can become larger or smaller, controlling how much light passes through the lens.

You will usually see aperture represented by numbers such as:

f/1.8, f/2.8, f/4, f/5.6, f/8, f/11 or f/16.

Here is the part that confuses many beginning photographers:

A smaller f-number represents a larger opening.

So f/2.8 allows more light through the lens than f/11.

Fortunately, you do not need to spend your afternoon doing optical mathematics to use aperture successfully.

What matters more is what aperture does to the photograph.

One of its most important effects is controlling depth of field, or how much of the scene appears acceptably sharp.

Imagine photographing someone standing in front of a garden.

Using a wider aperture such as f/2.8 can keep the person sharp while allowing the background to become beautifully soft.

That softer background helps separate the subject from everything around it.

Now imagine photographing a sweeping landscape.

You may want foreground rocks, middle-distance trees, and mountains farther away to all appear reasonably sharp.

In that situation, you might choose a smaller aperture such as f/8 or f/11.

The question is not simply:

What aperture should I use?

The better question is:

What do I want the viewer to notice?

Aperture helps answer that question.

Caption:

A shallower depth of field helps separate the praying
mantis from its surroundings, directing attention
toward the subject while allowing the
background to fall softly away

Photo Copyright:
Michael A. Buccilli.

That is something aperture can do very effectively.

Rather than allowing every detail in the background to compete for attention, the photographer can guide the viewer toward the subject.

Shutter Speed: Freeze Time
or Let It Move?

If aperture controls the opening inside the lens, shutter speed controls how long the camera records light.

And this is where photography starts doing something rather remarkable.

A camera can capture fractions of time that our eyes barely notice.

A shutter speed might be:

1/1000 of a second

or

1/250 of a second

or

1/30 of a second

or even several seconds long.

A fast shutter speed can freeze motion.

Imagine photographing a bird taking flight.

At a fast enough shutter speed, individual feathers may appear sharp even though the bird is moving rapidly.

The same principle works in sports photography.

A runner can be frozen mid-stride.

A baseball player can be captured during a swing.

A dog can appear suspended in the air during a jump.

But photographers do not always want to freeze movement.

Sometimes motion itself becomes part of the photograph.

A slower shutter speed can turn moving water into a soft flowing ribbon.

Car headlights can become streaks of light across a nighttime city scene.

Waves can blur around rocks along a shoreline.

The movement becomes part of the composition.

That means shutter speed is not merely a technical setting.

It is a storytelling choice.

Ask yourself:

Do I want this moment frozen, or do I want the photograph to show that something was moving?

The answer can completely change the character of the photograph.

ISO: When the Light
Gets Difficult

Then there is ISO.

ISO is often described as the camera's sensitivity to light. With modern digital cameras, the technical explanation is more complicated than that, but the practical idea is simple.

Increasing ISO allows the camera to produce a brighter-looking image when less light is available.

Imagine photographing outdoors on a bright afternoon.

There may be plenty of light, so ISO 100 or 200 could work beautifully.

Now imagine photographing inside a dim building or outdoors as evening approaches.

There is much less light available.

Increasing ISO may allow you to keep using a shutter speed fast enough to avoid unwanted motion blur.

But there is a tradeoff.

Higher ISO settings can introduce digital noise, which may appear as graininess or speckling in the photograph.

Modern cameras have become remarkably good at handling higher ISO levels, but a useful general rule remains:

Use the lowest ISO that comfortably allows you to create the photograph you need.

Notice that does not mean you must always use the lowest ISO possible.

Sometimes getting the photograph matters more than achieving perfectly clean pixels.

A slightly noisy photograph of a once-in-a-lifetime moment is usually far more valuable than a perfectly clean photograph that was never captured.

The Three Settings
Work Together

This is where the exposure triangle begins to make sense.

Aperture, shutter speed, and ISO do not exist in isolation.

They work together.

Imagine photographing a bird flying across the sky.

Your first priority may be freezing the bird's movement.

You choose a fast shutter speed.

But a fast shutter speed gives the camera less time to collect light.

You may compensate by opening the aperture wider.

If there still is not enough light, you might increase the ISO.

Now imagine photographing a waterfall.

This time, you want the water to appear smooth and flowing.

You deliberately choose a slower shutter speed.

Because the camera is gathering light for a longer period, you may need a smaller aperture or lower ISO to keep the image from becoming too bright.

The settings changed because your creative intention changed.

That is the part beginning photographers should remember.

The exposure triangle is not primarily about numbers.

It is about decisions.

Stop Searching for the "Perfect"
Camera Setting

One of the most common questions photographers hear is:

What settings should I use?

There is nothing wrong with asking that question while learning.

But eventually the question begins to change.

Instead of asking:

What setting should I use?

You begin asking:

What am I trying to create?

There is rarely one perfect setting for a particular subject.

Two photographers can stand beside each other photographing the same scene and create completely different photographs.

One might use a fast shutter speed to freeze waves crashing against rocks.

The other might place the camera on a tripod and use a slower shutter speed to turn those same waves into soft, ghostlike movement.

Neither photograph is automatically correct or incorrect.

They are interpretations.

The camera records light.

The photographer decides what to do with it.

Try This With Your Own Camera

You can begin understanding these settings without traveling anywhere exotic.

Find a simple subject around your home.

A coffee mug near a window works perfectly.

Yes, photography occasionally gives us legitimate professional reasons to involve COFFEE. ☕

Place the mug several feet in front of the background.

Take one photograph using a wider aperture.

Then take another using a smaller aperture.

Compare the backgrounds.

You should begin seeing how aperture changes depth of field.

Next, photograph something moving.

It could be someone walking through the room, water running from a faucet, a pet moving across the floor, or cars passing outside.

Try several different shutter speeds.

Do not worry about creating award-winning photographs.

Watch what changes.

Experiment.

Change something.

Look at the result.

Change it again.

Before long, the numbers stop feeling abstract because you have seen what they actually do.

Getting the Shot Is About
More Than Settings

Photography certainly involves equipment and technique.

But getting the shot often involves something much simpler:

paying attention.

Sometimes the difference between an ordinary photograph and a memorable one is waiting thirty seconds for the light to change.

Sometimes it is moving a few feet to remove a distracting object from the background.

Sometimes it is noticing a reflection everyone else walked past.

Sometimes it is recognizing that the clouds, shadows, colors, or movement in front of you are creating something temporary.

The camera settings matter because they give us tools for responding to those moments.

But the photograph begins before the shutter button is pressed.

It begins when you notice something.

Learning to See

That is ultimately what this Photography 101 series will be about.

We will talk about cameras, lenses, light, composition, exposure, equipment, different styles of photography, and many of the tools photographers use.

We may occasionally compare camera systems or explore why one photographer prefers a particular lens, camera body, or brand over another.

But we are not going to turn photography into a collection of intimidating formulas.

Photography is both technical and creative.

Understanding the technical side gives us more freedom to explore the creative side.

Aperture helps decide what receives attention.

Shutter speed determines what happens to movement.

ISO helps us work when the available light becomes challenging.

Together, those tools give photographers much greater control over the image.

But the most important tool remains the person standing behind the camera.

Because before there can be a photograph, someone has to notice that there is something worth photographing.

Sometimes that beauty appears in a dramatic wave breaking along the shoreline.

Sometimes it is found in the intricate details of a praying mantis only inches long.

And sometimes the most beautiful subjects are hiding in places we have walked past a hundred times.

The next photograph may already be waiting there.

You simply have to see it.

References:

Nikon USA – “A Basic Look at the Basics of Exposure”
This is probably our strongest overall reference because it directly covers the relationship between aperture, shutter speed, and ISO, including how shutter speed affects motion and how the three settings work together.
Nikon USA: A Basic Look at the Basics of Exposure

Nikon USA – “Understanding Maximum Aperture”
This supports our explanation of f-stops, aperture size, light, and depth of field, including why lower f-numbers correspond to larger lens openings.
Nikon USA: Understanding Maximum Aperture

Adobe – “Capturing Light: The Power of the Exposure Triangle”
This provides a good independent reference for the overall exposure-triangle concept and the creative relationship between aperture, shutter speed, and ISO.
Adobe: The Exposure Triangle