1. Aperture

Controls light and depth of field

Aperture refers to the opening inside your lens. It determines how much light enters the camera.

It is measured in f-stops (for example: f/1.8, f/4, f/8, f/16).

How it works:

• Lower f-number (e.g. f/1.8)

  • Larger opening

  • More light

  • More background blur

• Higher f-number (e.g. f/11)

  • Smaller opening

  • Less light

  • More of the scene in focus

When to use:

• Portraits → Lower f-number (for soft background blur)

• Landscapes → Higher f-number (for sharp detail throughout)

Aperture affects both brightness and how much of your image is in focus.

2. Shutter Speed

Controls motion and light duration

Shutter speed determines how long the camera’s shutter remains open.

It is measured in seconds or fractions of a second:

• 1/1000 (very fast)

• 1/250

• 1/60

• 1/10

• 1" (one full second)

How it works:

• Fast shutter speed (e.g. 1/1000)

  • Freezes motion

  • Lets in less light

• Slow shutter speed (e.g. 1/10 or 1")

  • Blurs motion

  • Lets in more light

When to use:

• Moving subjects → Faster shutter speed

• Low light → Slower shutter speed (with tripod if needed)

• Creative blur (water, movement) → Slower shutter speed

Shutter speed controls whether motion appears sharp or blurred.

3. ISO

Controls light sensitivity

ISO determines how sensitive your camera’s sensor is to light.

Common ISO values:

• 100

• 200

• 400

• 800

• 1600

• 3200+

How it works:

• Low ISO (100–200)

  • Less sensitive to light

  • Cleaner image

  • Best for bright conditions

• High ISO (1600+)

  • More sensitive to light

  • Brighter image

  • Introduces grain (noise)

When to use:

• Bright daylight → Keep ISO low

• Indoors or low light → Increase ISO if needed

Always try to keep ISO as low as possible while maintaining correct exposure.

How the Triangle Works Together

If you change one setting, you must compensate with another.

For example:

• If you lower your aperture (let in more light), you may need to:

  • Increase shutter speed

  • Or lower ISO

• If you use a faster shutter speed (less light), you may need to:

  • Open the aperture

  • Or increase ISO

The goal is balanced exposure without sacrificing creative control.

A Simple Starting Formula for Beginners

In daylight:

• ISO 100

• Aperture f/4–f/8

• Adjust shutter speed until exposure looks correct

In low light:

• Open aperture (lower f-number)

• Slow shutter speed

• Increase ISO only when necessary

Common Beginner Mistakes

• Increasing ISO too quickly

• Using a shutter speed that’s too slow (causing blur)

• Forgetting that aperture affects depth of field

• Changing all three settings at once

Adjust one setting at a time and observe what changes.

Final Thought

The exposure triangle is not about memorising numbers — it’s about understanding the relationship between light, motion, and focus.

Once you understand how aperture, shutter speed, and ISO work together, you move from letting the camera decide — to making intentional creative choices yourself.

That’s the point where photography truly begins.