Week 2: Mastering the Exposure Triangle
Unlocking the power of Aperture, ISO, and Shutter Speed
Session Outline
Lanyards & Housekeeping
Course logistics and setup
Student Image Review
Discuss homework from Week 1
The Exposure Triangle
Understanding ISO, Shutter Speed, Aperture
Understanding PSAM Modes
Program, Shutter, Aperture, Manual
Practical Tasks & Homework
Hands-on camera practice
Intro to Lightroom
Basic workflow and organization
What is the Exposure Triangle?
A fundamental concept used to explain how three critical camera settings interact to control the amount of light hitting your sensor.
ISO
The sensitivity of your camera's sensor to light.
Low ISO (100-400): Less sensitive, cleaner images, requires more light
High ISO (1600+): More sensitive, works in low light, introduces grain/noise
Shutter Speed
The duration the shutter remains open.
Fast (1/500s - 1/8000s): Freezes motion, requires more light
Slow (1/30s - 30s): Creates motion blur, captures more light
Aperture
The size of the opening in the lens (iris).
Wide (f/1.4 - f/2.8): Large opening, shallow depth of field, more light
Narrow (f/11 - f/22): Small opening, deep depth of field, less light
ISO: Sensor Sensitivity
"Higher ISO helps in low light but adds grain—just like turning up the volume adds background noise."
Low ISO (100-400)
Best for bright light conditions. Captures maximum detail, rich tones, and accurate color with zero noise.
Quality: Maximum
High ISO (1600+)
Necessary for low light or fast action. Increases sensitivity but introduces digital noise (grain).
Quality: Reduced
Noise Types
Monochromatic:
Similar to classic film grain.
Chromatic:
Unwanted color speckles (the "bad" kind).
Technical: Digital Artifacts
Auto ISO Tip: Use bands like 100-800 or 1600-6400 for flexibility.
Common ISO Values:
100 • 200 • 400 • 800 • 1600 • 3200 • 6400
Each doubling increases sensitivity by one "stop" of light
Shutter Speed: Freezing vs. Blurring
The Handheld Rule
To avoid camera shake, your shutter speed should be equal to or greater than your focal length.
Example: 50mm Lens = 1/50s or faster.
Fast (1/500s+)
Freezes action and sharpens moving subjects. Lets in less light.
Perfect for sports, wildlife, children, anything in motion.
Slow (1/4s+)
Blurs motion (water, clouds) for creative effect. Lets in more light.
Perfect for waterfalls, light trails, night scenes, creative blur.
Interaction Note: Fast shutter speeds often require a higher ISO or a wider aperture to compensate for the reduced light duration.
Common Shutter Speed Values:
1/8000s • 1/4000s • 1/2000s • 1/1000s • 1/500s • 1/250s • 1/125s • 1/60s • 1/30s • 1/15s • 1s • 5s • 30s
Each doubling of time (e.g., 1/250s to 1/125s) equals one "stop" of light
Aperture: The Lens Opening & DOF
Large Aperture
Small f-number (e.g., f/2.8)
The iris is wide open, allowing a high volume of light to hit the sensor. This creates a Shallow Depth of Field, where the subject is sharp but the background is blurred.
Small Aperture
Large f-number (e.g., f/16)
The iris is narrowed, significantly reducing the light volume. This results in a Deep Depth of Field, ensuring sharpness from the foreground all the way to the background.
The Trade-off
Closing the aperture (higher f-number) reduces light. To maintain exposure, you must compensate by using a slower shutter speed or increasing the ISO.
Common Aperture Values:
f/1.4 • f/2 • f/2.8 • f/4 • f/5.6 • f/8 • f/11 • f/16 • f/22
Each step equals one "stop" of light (e.g., f/2.8 to f/4)
PSAM: Taking Control
Understanding when to let the camera help and when to take full manual command of your exposure.
P (Program)
Camera decides: Aperture + Shutter Speed
You control: ISO, Exposure Compensation, White Balance
Best for: Quick shooting when lighting changes fast
S/Tv (Shutter Priority)
You control: Shutter Speed
Camera decides: Aperture
Best for: Sports, action, motion control
A/Av (Aperture Priority)
You control: Aperture (Depth of Field)
Camera decides: Shutter Speed
Best for: Portraits, landscapes, depth of field control
M (Manual)
You control: Everything (Aperture + Shutter Speed + ISO)
Camera decides: Nothing (you're in full control)
Best for: Studio, consistent lighting, full creative control
Homework: The PSAM Challenge
Capture one image in each of the four exposure modes (P, S/Tv, A/Av, M). Document your camera settings for each shot: Aperture, Shutter Speed, and ISO.
Submission Requirements
- • 4 images total (one per mode)
- • Label each image with the mode used
- • Include camera settings (Aperture, Shutter, ISO)
- • Upload to Google Drive by Sunday evening
Evaluation Criteria
- • Correct use of each exposure mode
- • Proper exposure (not too dark/light)
- • Clear subject matter
- • Understanding demonstrated through settings