As a photographer based in Portland, Oregon, I have chased countless moments of light and shadow in the Pacific Northwest region. Whether it’s raindrops freezing on Douglas fir trees or blurring the evening commuting traffic in downtown Seattle, I can’t do without those three core photography parameters: shutter speed, aperture, and ISO.
In theory, I know their function, but truly transforming knowledge into works often feels like piecing together a puzzle with a few missing pieces. Later on, I discovered that there is no one size fits all parameter for any scene. The key is to first clarify the feeling you want the photo to convey before making a choice.
Today, let me use the method I taught beginners in a photography workshop to take you through the three elements of exposure one by one, and combine them with practical cases to show you how to flexibly apply them.

Shutter speed: Control dynamics, tell stories

The shutter speed determines the time for the camera’s photosensitive element to receive light. You can imagine it as’ blinking ‘:
Slow Blink: More Light, but Easy to Blurry Dynamics
Quick Blink: Freeze the frame, but the incoming light decreases
Commonly used fractions (such as 1/500) or integers (such as 2 seconds) in cameras.
When to use high-speed shutter (1/250 second and above)
Suitable for freezing fast actions:
Wild animals: Hummingbirds flap their wings in 1/1000 second, deer take 1/500 second to step
Sports events: Football 1/1250 seconds, Basketball 1/2000 seconds
Splashing water: For example, I captured the moment when a black dog shook off water droplets in 1/640 second

📸 Case: While filming a mountain bike race in Bend, I captured the splashing soil and the tension of the riders in 1/2000 second, and needed continuous shooting to capture the most exciting moment.

When to use a low-speed shutter (1/60 second or less)
Suitable for creating a flowing and artistic atmosphere:
Night traffic flow: 10-30 seconds, dimming track for headlights
Rivers/Oceans: 1-5 seconds, gentle and smooth water flow
Creative portrait: 1/30 second blur of skirt, but maintain facial clarity
💡 Professional tip: When it is less than 1/60 second, be sure to use a tripod or support unless you intentionally pursue blurring effects.
Aperture: Shapes the focus and guides the line of sight
Aperture is the size of the lens aperture, which determines:
Light intake quantity
Depth of Field (Clear Range)
Remember: the smaller the f-value → the larger the hole → more incoming light → shallow depth of field; Vice versa.
Shallow Depth of Field (f/1.4-f/4): Highlighting the Subject
Portrait photography: f/1.8-F/2.8, blurred background
Macro photography: f/2.8-F/4, focusing on details
Food photography: f/2.8, making food more attractive
📸 Case: When taking a photo of my neighbor’s black cat, I used f/2.8 to blur the background sofa into soft light spots, and the cat became the only focus.
Deep depth of field (f/8 – f/22): Clear panoramic view
Landscape photography: f/11-f/16, the foreground is as clear as the distant mountains
Architectural photography: f/8-f/11, maintaining sharp details
Group photo: f/8, ensure everyone is in focus
📸 Case: When shooting scenery in the Cascades Mountains, I used f/16 to make wildflowers and distant mountains appear clearly.
Sensitivity (ISO): Brightens the image, but beware of noise
ISO controls the sensitivity of photosensitive elements to light. You can think of it as radio volume: increasing it can hear more, but it can also bring noise.
Low ISO (100-400): Low noise, sharp image quality → Suitable for sufficient lighting during the day
High ISO (800-6400+): Increases brightness, but with noticeable graininess in the image → suitable for low light or requiring high-speed shutter speeds

📸 Case: During night photography at Portland train station, I used ISO 12800 to maintain brightness, but visible noise appeared in the sky.

💡 The Golden Rule: Always start shooting from the lowest ISO. If the image is too dark, try increasing the aperture or lowering the shutter speed first, and then increasing the ISO.
Practical combination of exposure of three elements
Instead of mastering all three elements at the same time, let’s first clarify the question: What kind of feeling do I want this photo to convey?
Scenario 1: Sunset Beach Shooting Friends
Aperture: f/2.8, blurring the background sea surface
Shutter: 1/125 second, ensuring clarity and allowing light to enter
ISO: 100 → 400, moderately brightening
Scene 2: Shooting Waterfalls in the Woods
Shutter: 1 second, make the water flow smooth
Aperture: f/16, avoid overexposure
ISO：100， Keep the picture quality clean
Final reflection: Focus on practice rather than pursuing perfection
When I first started learning photography, I used to take over twenty shots of the same tree, changing different parameters each time just to observe the changes in the image.
👉 I suggest you practice like this:
Do you want to ‘freeze’ or ‘flow’?
Do you want focus or clear panoramic view?
Adjust the shutter speed and aperture according to the answer ISO。
There is no one correct setting for photography, only settings that can help you tell a story.