ISO, Aperture, and Shutter Speed Explained Simply | Manual Mode Made Easy

May 6

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Hey friend! I’m Leah—a wedding photographer and educator—and if you’ve ever felt overwhelmed trying to figure out how to shoot in manual mode, you’re not alone. Today, we’re going to break down the exposure triangle in a way that’s super simple and easy to understand.

The exposure triangle is made up of three camera settings that work together to determine how your image turns out: ISO, aperture, and shutter speed. These settings control how bright or dark your photo is, how sharp or blurry it looks, and how much motion is captured. They're the secret to confidently using manual mode—and honestly, the more you practice, the more natural it becomes.

What Is the Exposure Triangle?

Think of ISO, aperture, and shutter speed as three parts of a team. They work together to control how much light hits your camera’s sensor and what your final image looks like.

Yes, it feels like a lot at first—but once you understand what each part does, it starts to feel like riding a bike.

ISO: Your Camera’s Sensitivity to Light

ISO controls how sensitive your camera is to the light around you.

Lower ISO: Best for bright light (like shooting outside on a sunny day). Clean image with little to no grain.
Higher ISO: Needed for darker environments. Brightens the photo but can add grain (also called "noise").

Quick Tip: Try to keep your ISO as low as possible while still getting enough light. Modern cameras handle high ISO better than they used to, so don’t stress if you need to bump it up now and then.

Aperture: How Much Light Gets In + Background Blur

Aperture is the size of the lens opening—and it affects both brightness and how blurry your background is (this is called depth of field).

Lower f-stop (like f/1.8): Bigger opening, more light, and a blurrier background (great for portraits).
Higher f-stop (like f/8 or f/16): Smaller opening, less light, and a sharper background (great for landscapes or group shots).

Quick Tip: Remember—lower number = blurrier background + more light, higher number = more in focus + less light.

Shutter Speed: How Long Light Hits the Sensor + Motion Control

Shutter speed is how fast your camera takes the photo.

Fast shutter (like 1/1000): Freezes motion—perfect for fast-moving kids or sports.
Slow shutter (like 1/30): Shows motion—use it when you want a bit of blur for creative effect (like dancing or spinning).

Quick Tip: Faster shutter = darker photo. Slower shutter = brighter photo (but watch out for blur!).

Quick Recap:

ISO = Sensitivity to light
Aperture = Light + background blur
Shutter Speed = Light + motion

Each one plays a role—and they all work together to create your final image.

How They Work Together (With Real Examples)

Let’s walk through a few simple examples so you can see how the exposure triangle comes to life:

1. Bright Sunny Day – Family Session

ISO: Low (100–200)
Aperture: Around f/2.8 for that dreamy blurry background
Shutter Speed: Fast (1/500 or higher) to freeze movement, especially with kids!

2. Golden Hour – Soft, Glowy Light

ISO: 100–200 (or 400 if it’s dimming)
Aperture: f/2.8 to keep faces in focus and background soft
Shutter Speed: 1/500 or slightly slower to let in more light (or slower for some motion blur)

3. Motion Blur – Couples Session

ISO: Low (since it’s likely overcast or soft light)
Aperture: f/4 or higher to balance the brightness
Shutter Speed: Slow (around 1/125) to intentionally capture motion

Final Thoughts: There’s No Perfect Setting

Here’s your reminder: there’s no single perfect setting for every photo.

You might see other photographers share their settings online, and that’s great for learning—but the truth is, every situation is different. Lighting, subjects, movement—it all matters. Learning how to adjust on the fly is what helps you grow.

And the best way to get better? Practice. A lot of it. Photograph your kids, your dog, your coffee mug—whatever it takes to experiment and get comfortable with your settings.

The more you shoot, the more your photos will start to feel like YOU.

You're Not Just Learning—You're Building Your Style

Every photo you take in manual mode helps you build your own unique style. You’re not just learning camera settings—you’re creating your own artistic voice.

If this blog helped you understand the exposure triangle better, I’d love for you to check out the video version above—or explore more of my free resources to make your photography journey even easier.

Thanks for being here. You’ve got this. Keep building what you love.

Now that you’ve got a better understanding of ISO, aperture, and shutter speed…

If you’ve ever thought about starting your own photography business—or even just wondered what it would take—I put together a blog post that walks you through exactly how I’d do it if I were starting from scratch in 2025.

It’s real, it’s doable, and it’s written with you in mind.

Here’s the link if you want to check it out: How to Start a Photography Business in 2025