What circle of confusion or Sensor Size is used in the ExpoAperture Depth of Field Guide calculations?
The proliferation of different size image sensors in digital imaging has resulted in the loss of depth of field scales from nearly all modern DSLR lenses. To help photographers overcome the absence of these scales, along with the difficulty of adjusting for different sensor and film sizes, the ExpoAperture2 Depth-of-Field Guide was designed to allow the user to adjust for a camera’s specific sensor, or film size. An included reference chart provides the conversion factors necessary to use the Guide with nearly any camera, regardless of sensor size or film format — from the 4/3 system to APS-C sensors, to full frame 35mm, to medium and large format film sizes.
