What is ISO, Shutter Speed, and Aperture? A Simple Guide

If you're new to photography or videography, you've probably heard terms like ISO, shutter speed, and aperture tossed around a lot. These three settings make up the Exposure Triangle—a key concept every content creator and photographer should understand. In this guide, we'll break each one down in simple terms so you can finally take control of your camera and capture professional-looking shots.

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4/21/20252 min read

📸 1. What is ISO?

ISO refers to your camera’s sensitivity to light. The lower the number, the less sensitive it is; the higher the number, the more sensitive it becomes.

Low ISO (e.g., 100–400): Great for bright daylight; produces clean, sharp images
High ISO (e.g., 800–3200 or more): Useful in low-light but can cause grain or “noise” in your images

✅ Pro Tip: Always try to keep ISO as low as possible for the cleanest quality, and only raise it when necessary.

⏱ 2. What is Shutter Speed?

Shutter speed determines how long your camera's sensor is exposed to light.

Fast shutter speeds (e.g., 1/1000s) freeze motion—perfect for sports, wildlife, or action shots
Slow shutter speeds (e.g., 1/30s or slower) capture motion blur and are great for artistic shots like waterfalls or night photography

✅ Pro Tip: Use a tripod when using slow shutter speeds to avoid camera shake.

🌕 3. What is Aperture?

Aperture refers to the size of the opening in your lens, which affects how much light gets in and how blurry your background is.

Low f-stop (e.g., f/1.8): Wide opening, more light, and beautiful background blur (bokeh)
High f-stop (e.g., f/16): Narrow opening, less light, and more of the scene in focus

✅ Pro Tip: Use a lower f-stop for portraits and a higher f-stop for landscapes where you want everything sharp.

🔺 Understanding the Exposure Triangle

ISO, shutter speed, and aperture work together to control how bright or dark your image is.

Here’s how they interact:

Need more light? Slow down the shutter, open up the aperture, or raise the ISO
Too bright? Speed up the shutter, use a smaller aperture, or lower the ISO

Changing one setting often means adjusting the others to keep the exposure balanced.

📷 Real-World Example

Imagine you’re taking a portrait in soft indoor lighting:

ISO: 800 (to help brighten the image)
Shutter Speed: 1/125s (fast enough to avoid blur)
Aperture: f/2.8 (for a beautiful background blur)

Together, these settings give you a bright, sharp portrait with a soft background.

📦 Final Thoughts

Mastering ISO, shutter speed, and aperture is like learning the ABCs of photography. Once you understand how they work, you'll have full control over your camera and the creative power to capture photos exactly how you envision them.

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