Day 4 — “Aperture & Background Blur (Depth of Field)”

Aperture & Background Blur: f/1.8 vs f/16
Today you’ll control depth of field—how much of your photo looks sharp from front to back. Think of aperture as the “background blur” lever.

### The basics

• Low f-number (f/1.8–f/2.8): Shallow depth of field → blurrier backgrounds. Great for portraits and isolating a subject.
• Mid f-number (f/4–f/8): Moderate depth → balanced sharpness. Good everyday setting.
• High f-number (f/11–f/16): Deep depth of field → more in focus. Useful for groups, products, landscapes.

### How to set it (generic)

1. Choose A/Av mode.
2. Set f/2.8 (or your lens’s lowest f-number) for blur; set f/8–f/16 for more in focus.
3. Focus where it matters most (use single-point AF from Day 3).

> Note: At higher f-numbers, your shutter speed can get slower. If it drops too low, raise ISO or add light.

### 5-minute exercise

• Put an object 3–6 feet from a background (a mug in front of books works well).
• Take the same photo at f/2.8, f/5.6, f/8, f/16.
• Compare: notice how the background transitions from soft to detailed.

### Quick wins

• Portraits: f/2–f/2.8 (watch your focus—hit the eye).
• Two people side-by-side: f/3.5–f/4.
• Family/group: f/5.6–f/8.
• Products/tabletop: f/8–f/11.
• Landscape: f/8–f/11 (start here; adjust as needed).

Tomorrow: We’ll talk distance & focal length—two more levers that change depth of field.