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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

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Jean-Pierre La Forest

Photographer / Videographer at Studio JPIC
Jean-Pierre La Forest is a photographer and videographer based out of Florenceville-Bristol, NB, Canada. JP specializes in commercial and tourism photography and videography, where he helps businesses, artists, and towns to market themselves. He also teaches the art of photography on his YouTube channel and blog. You can reach him on

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