TECH SUPPORT Light it Up Q. What exactly is a Backlit sensor? A. Also known as a back-side illuminated or BSI sensor, this is a type of camera sensor used in compacts from Canon, Nikon, Sony, and others. The technology was developed to improve the light-gathering capability of the smaller chips used in these cameras, and the term refers to the way circuitry is burned onto sensor substrates during their manufacture. With conventional sensors (both CMOS and CCD), circuitry is laid into the sensor’s top surface surrounding its pixels. That results in smaller pixels that are recessed from the sensor surface, which compromises efficiency. Backlit sensors, on the other hand, have their circuitry located beneath the pixels on the rear of the silicon substrate (hence “backlit”), which is shaved thin to accommodate it. Larger pixels that are relatively flush with the sensor’s surface are the result, with significant gains especially in low-light performance. |