BSI, or Back Side Illuminated sensors are also known as ‘Back Illuminated’ sensors. They are a revision of traditional sensor designs which increases the light gathering efficiency of the sensor to deliver higher sensitivity, less noise and better all round image quality.
All sensors have light-sensitive photosites. On older sensor designs, these are partly obscured by the circuitry needed to collect and transfer the light values to the camera’s processor. This means that only a percentage of the sensor surface is actually light sensitive – some of it is wasted by the circuitry in front.
Ideally, there should be no