What are the pixel dimensions of the ALEXA sensor?
The ALEV III sensor has 3392 x 2200 pixels that can be used for generating an image. There are actually more pixels on the sensor, but these extra pixels are used for calibration and other purposes and cannot be used for generating an image. ALEXA uses a 16:9 area from that sensor and not the whole sensor area, in order to keep the processing power needed (and thus the cost of the processing components, manufacturing cost and sales price) at our target values. For the ProRes recording and HD-SDI outputs we are reading 2880 x 1620 pixels (16:9) from the sensor. They are then debayered and downscaled by a factor of 1.5, which leads to a beautiful 1920 x 1080 HD image. 2880 x 1620 pixels is equivalent to an active sensor area of 23.76 x 13.37 mm. For the ARRIRAW T-link output we are also reading 2880 x 1620 pixels (16:9), but those are neither debayered nor downscaled in the camera. Instead, they can be debayered in post with a number of optional downscale factors, including a factor that
