Depth of Field Calculator

| Added in Miscellaneous

The Depth of Field Calculator helps photographers determine how much of their image will be in acceptable focus. Understanding depth of field is crucial for controlling what appears sharp in your photographs.

Formula

The depth of field is calculated using:

[\text{DOF} = \frac{2 \times u \times N \times c}{f^2}]

Where:

  • u is the distance to the subject (in meters)
  • N is the f-number (aperture setting)
  • c is the circle of confusion (in millimeters)
  • f is the focal length (in millimeters)

Calculation Example

For a portrait photograph with these settings:

  • Distance to subject: 10 meters
  • Aperture: f/11
  • Circle of confusion: 0.025mm (full-frame camera)
  • Focal length: 85mm lens

Calculation:
[\text{DOF} = \frac{2 \times 10 \times 11 \times 0.025}{85^2}]

[\text{DOF} = \frac{5.5}{7225} = 0.00076 \text{ m} \approx 0.76 \text{ mm}]

This indicates a very shallow depth of field, typical for portrait photography with a telephoto lens at wide aperture.

Factors Affecting Depth of Field

Aperture (f-number)

  • Large aperture (f/1.4, f/2.8): Shallow DOF, blurred background
  • Small aperture (f/11, f/16): Deep DOF, more in focus

Focal Length

  • Wide angle (24mm, 35mm): Greater DOF
  • Telephoto (85mm, 200mm): Shallower DOF

Distance to Subject

  • Close distance: Shallower DOF
  • Far distance: Greater DOF

Camera Sensor Size

  • Full-frame: CoC ≈ 0.025-0.030mm
  • APS-C crop: CoC ≈ 0.015-0.020mm
  • Micro Four Thirds: CoC ≈ 0.012-0.015mm

Photography Applications

Portraits: Use shallow DOF (f/1.8-f/4) with 85mm lens to isolate subject from background.

Landscapes: Use deep DOF (f/11-f/16) with wide-angle lens to keep foreground and background sharp.

Macro: Very shallow DOF due to close focusing distance; use smaller apertures (f/8-f/16) to increase sharpness.

Street Photography: Moderate DOF (f/5.6-f/8) with 35mm lens for balance between subject isolation and context.

Frequently Asked Questions

Depth of field is the range of distance within a photograph that appears acceptably sharp. A shallow depth of field means only a small area is in focus, while a deep depth of field means more of the scene is sharp.

Circle of confusion (CoC) is the maximum acceptable blur spot that still appears sharp to the human eye. For full-frame cameras, this is typically 0.025mm to 0.03mm. Crop sensor cameras use smaller values.

To achieve a shallow depth of field with blurred backgrounds, use a wide aperture (low f-number like f/1.8 or f/2.8), longer focal length, and get closer to your subject.

Smaller apertures (higher f-numbers like f/16 or f/22) create greater depth of field with more of the scene in focus. Larger apertures (lower f-numbers like f/1.4 or f/2.8) create shallower depth of field with less in focus.