A Triple Conversion Gain (TCG) sensor with all-pixel auto focus based on 2PD of 1.4 um-pitch has been demonstrated for mobile applications. TCG was implemented by sharing adjacent Floating Diffusion (FD) without adding other capacitor. TCG helps to reduce the noise gap or slow the noise increase as user gain increases. An image with a Dynamic Range (DR) of 82.4 dB through a single exposure can be obtained through intra-scene TCG (i-TCG). Through this, a wider range of illuminance environments can be captured in the image. In addition, a more natural image can be obtained by reducing the SNR dip in one image by using TCG.