Sensor sizes: millimeters vs inches?
In the EXIF window, PTGui will show you the size of the optical sensor in millimeters (if the data or your camera is available). Most manufactures however will state the sensor size in fractions of an inch (e.g. 1/2.5″). The inch-designation dates back to TV camera tubes in the 50s and it does not appear to be mathematically related to the actual sensor size. For more information, read Sensor Sizes at DPReview.
