Bellows Extension Calculator

Calculate exposure compensation and magnification for bellows macro photography.

Bellows & Lens Settings

Total distance from film/sensor plane to lens optical center

Magnification

1.0:1
1.00x life size

Exposure Compensation

Bellows Factorx4.00
Exposure Compensation+2.0 stops
Effective Aperturef/16.0

Compensated Exposure

Base Shutter1/60
Compensated Shutter1/15

Optical Details

Working Distance100.0mm
Depth of Field0.96mm
Subject Coverage36.0mm x 24.0mm

Extension Reference

Extension for 1:1100mm

For 1:1 magnification, extension equals 2x focal length

Bellows Photography Tips

• Use a sturdy tripod - vibration is magnified at high magnification

• Focus by moving the camera/subject, not the lens

• Stop down for more DOF but watch for diffraction

• Consider focus stacking for greater depth of field

• Use mirror lock-up or electronic shutter

• Flash lighting helps freeze subject movement

Bellows Factor Formula

Magnification = (Extension - FL) / FL

Bellows Factor = (1 + M)²

Exposure Comp = log₂(Bellows Factor)