# How can I compute the size of the camera sensor which is involved in recording video

by Filippo Bandini   Last Updated January 18, 2018 22:18 PM

THe resolution of the Sony Cyber-shot DSC-RX100 is 5472 x 3648 pixels.Sensor width = 13.20 mm, Sensor height = 8.80 mm, aspect ratio=1.5. However, when taking videos the resolution changes to 1,920 x 1,080 (16:9 aspect ratio). SO that suggests that the camera crops part of the sensors when taking videos. Is it possible to know/compute the size of the part of the sensor that is involved in taking videos?

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Make a setup with a couple of rulers arranged horizontally and vertically, and the camera on a tripod, spaced so that the rulers fill the entire frame. Take a still picture, then a short video, without moving the camera. The change in field of view will be proportional to the amount of the sensor being used.

Mark Ransom
January 18, 2018 22:35 PM

The sensor size is 8.8mm height by 13.2mm length. This is a 1.5 ratio i.e. 8.8 X 1.5 = 13.2.

When shooting video, the ratio changes to 16:9. This is a fraction 16 ÷ 9 = 1.7778 (in decimal format). If we know the dimensions of one of the two sizes of a rectangle, we can compute the other using this decimal fraction. Likely in video mode, full length of the sensor is being utilized. Thus the revised height is 13.2 ÷ 1.7778 = 7.4249. That’s the height in millimeters. The video format becomes 7.4mm height by 13.2mm length.

Alan Marcus
January 18, 2018 22:45 PM