Minimum Focus Distance Calculator

Calculate the minimum focus distance required for a lens based on its focal length, aperture, and subject magnification

Input Parameters

For static subjects, use 1×. For close-up photography, use values > 1.

Calculation Results

Calculation Formula

Minimum Focus Distance (mm) = Focal Length × (Aperture × 2) × Magnification

Where:
Focal Length: The distance from the lens to the image sensor when the lens is focused at infinity
Aperture: The f-number of the lens (e.g., f/2.8, f/4)
Magnification: The size of the subject in the image compared to its actual size

Result Interpretation

This is the minimum distance your lens needs to be from your subject to achieve sharp focus. For macro photography, you'll need to be closer than this distance.

Minimum Focus Distance Calculator Calculator Usage Guide

Learn how to use the Minimum Focus Distance Calculator and understand its applications in photography

How to Use This Calculator

  1. Enter your lens's focal length in millimeters (mm)
  2. Input the aperture value (f-number, e.g., f/4, f/5.6)
  3. Set the subject magnification:
    • Use 1× for static subjects (like landscapes or portraits)
    • Use values > 1× for macro photography (e.g., 1.5×, 2.5×, etc.)
  4. Click the "Calculate" button to determine the minimum focus distance
  5. The result will show the minimum distance from your subject for sharp focus

Understanding Minimum Focus Distance

The minimum focus distance is the closest distance at which a lens can focus on a subject and produce a sharp image. This value is important for several photography applications:

  • Portrait Photography: Helps ensure your subject's eyes are in focus
  • Macro Photography: Essential for close-up shots of small subjects
  • Wildlife Photography: Allows you to maintain a safe distance from animals
  • Street Photography: Helps determine how close you can get to your subject

Important Considerations

Remember that this calculator provides the theoretical minimum focus distance. In practice, you may need to focus slightly beyond this distance for maximum sharpness, especially with wide apertures (small f-numbers). Also, this calculation doesn't account for lens extension when using macro modes.