Find the magnification ratio of a subject image on the sensor.
A reproduction ratio compares the image size on the sensor to the real subject, so 0.5 means the subject appears at half its real size. Lenses marketed as macro reach at least 1x, and the ratio tells you the smallest subject that fills the frame.
Macro Reproduction Ratio
Magnification = sensor width / subject width
Magnification = sensor width / subject width A reproduction ratio compares the image size on the sensor to the real subject, so 0.5 means the subject appears at half its real size.
Lenses marketed as macro reach at least 1x, and the ratio tells you the smallest subject that fills the frame.
This calculator takes 2 inputs: Sensor width, Subject width. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.