Pocket Telemeter - Range Finder is an application that will let you calculate the distance between you and an object and its height. It is simple and quick to use, just type the height at which you hold your device, aim at the base of the object and you will get the distance, you can also use the distance to get the object height.
The application uses some mathematical formulas so the error percentage is very low and it supports both m. and ft. units of measurement. Also you can keep the current distance by pressing the hold button.