Electroluminescence (EL) diagnosis has been widely used as a powerful tool to analyze solar cell performance photographically. Portable Near Infrared (NIR) camera with high-sensitive Si senor will be demonstrated to detect weak EL from PV cells and modules. Precise evaluation will be feasible for various kinds of solar cells (crystalline Si, amorphous Si, CIGS thin film cells, etc.) in dark rooms. In addition, with the help of appropriate power source PV modules and strings of installed mega-solar systems can be inspected “on site” and “as is” states, which will be valuable to maintain the long reliable performance of PV systems.