The zRuler or Smart Zoom Camera Ruler has been developed to enable iPhone users to measure directly distances between 15 cm (~ 5.9 in ) and 100 cm (39.4 in) without using tricks or other intermediary references.How to measure:- Run the full calibration process.- Place the iPhone with the display up with the lower edge at one end of the distance to measure.- Keeping the lower edge of the iPhone touching the surface to measure, gently raise the upper edge by rotating the device around the lower edge.- Aim the crosshairs on the upper section of the screen to the end of the distance you intend to measure.- Wait until the distance reading below crosshairs stabilizes.- Press the "Measure" button to retain the reading.To the moment zRuler measures fairly accurately distance up to 60 cm and distances up to 100 cm with up to 5% margin error.zRuler v1.0 also works best if the lower edge of the iPhone is horizontal.The measurement accuracy depends also on a clear focus of the distant end of the distance to measure and constant illumination.Further versions will bring max length measurement up to 10 m (~ 33 feet), automatic calibration and measurement.Very important: Due to the fact that this software uses the configuration of the case of the device the current version of the zRuler is designed only for iPhone 4. Due to the specific use of iPad the iPad version will be decided later. App reviews will be taken into consideration.
