Circle of Confusion calculator

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What is a Circle of Confusion?

The Circle of Confusion (CoC) is the size of the blur spot which our eyes cannot distinguish from a point.


  1. Choose the sensor size of your camera.
  2. (Advanced)Select the dividend for the Circle of Confusion calculation. On this site we use the d/1500 calculation, which represents resolving 5 lines per millimeter on a print measuring 30 cm in diagonal. d/1730 is sometimes known as the Zeiss Formula, though Zeiss recommends d/1000 as a traditional standard, and d/1500 as a modern standard. If you are unsure, please select 1500.
1. Sensor size: mm x mm
2. d/

Sensor Diagonal Size: mm
Circle of Confusion: mm