Image sensor and operation method of the image sensor

An image sensor, comprising:

• a pixel array including a plurality of white pixels, a plurality of color pixels, and a plurality of auto focus (AF) pixels;
• and
• a row driver configured to generate signals applied to the pixel array,
• wherein each of the plurality of white pixels, the plurality of color pixels, and the plurality of AF pixels of the pixel array comprises a photodiode and a transfer transistor serially connected to the photodiode,
• wherein a first shared pixel including some of the plurality of white pixels and the plurality of color pixels comprises a first conversion gain transistor and a second conversion gain transistor each configured to control a conversion gain of the first shared pixel,
• wherein a second shared pixel including some of the plurality of white pixels and the plurality of color pixels and at least one AF pixel comprises a third conversion gain transistor and a fourth conversion gain transistor each configured to control a conversion gain of the second shared pixel,
• wherein a white pixel control line is connected to a gate of the transfer transistor included in each of the plurality of white pixels,
• wherein a color pixel control line is connected to a gate of the transfer transistor included in each of the plurality of color pixels,
• wherein an AF pixel control line is connected to a gate of the transfer transistor included in each of the plurality of AF pixels, and
• wherein the first conversion gain transistor, the second conversion gain transistor, the third conversion gain transistor, and the fourth conversion gain transistor are connected to different conversion gain control lines, respectively.