Macro Photography Calculator

Magnification ratio, DOF, and working distance.

Focal length (mm)

Aperture (f/)

Subject width (mm)

Sensor width (mm)

Circle of confusion (mm)

Extension tube (mm)

Tab to move between fields

Magnification (×)

Depth of field (mm)

0.96

Effective aperture (f/)16

Working distance (mm)200

Light loss (stops)2

Airy disk (µm)21.5

Diffraction limited?0

How to Use This Calculator

Enter the lens focal length, minimum focusing distance, and maximum magnification ratio.
Set the subject size in mm that you want to fill the frame.
Input the aperture you plan to use.
Review the Depth of Field at the selected magnification and aperture.
Use the Extension Tube Required output to reach magnifications beyond the lens minimum.

How the result changes with Subject width (mm)

Focal length (mm): Macro lens focal length in mm.
Aperture (f/): Set aperture f-number.
Subject width (mm): Width of the subject being photographed in mm.
Sensor width (mm): Camera sensor width (36mm for full-frame, 23.5mm APS-C).
Circle of confusion (mm): Acceptable CoC in mm (0.03 for FF, 0.02 for APS-C).
Extension tube (mm): Total extension tube length added (0 for none).

Magnification (×): Image magnification ratio (1.0 = life-size).
Effective aperture (f/): Actual f-number at sensor accounting for magnification.
Depth of field (mm): Total depth of field in millimeters.
Working distance (mm): Approximate distance from lens front to subject.
Light loss (stops): Exposure compensation needed due to magnification.
Airy disk (µm): Diffraction Airy disk diameter at effective aperture.
Diffraction limited?: 1 = diffraction dominates sharpness, 0 = still resolving.

Identify Input Parameters
4 parameters
Focal length (mm) = 100, Aperture (f/) = 8, Subject width (mm) = 36, Sensor width (mm) = 36 = 6 input(s) provided
Calculate Magnification
Magnification = magnification + extensionTubeMm / focalLength
1 = 1
Calculate Depth of field
0.96 = 0.96
Calculate Effective aperture
Effective aperture = aperture * (1 + totalMagnification)
16 = 16
Calculate Working distance
200 = 200