This is a difficult question to answer since it depends on so many factors. For example is the size of the leak a major factor. This camera works just like any other camera regarding this, just think of an object moving away from you this object will appear smaller and smaller using any camera. Feed-back given is that 95% of the work can be done using the standard 25 mm lens. A normal working distance for this would be 1 - 10 meters.