An image sensor pixel has variable conversion gain to prevent overexposure of the pixel without reducing the exposure period. Under dim lighting conditions, the pixel operates with high conversion gain and is highly sensitive to light. When the incident light is bright, the pixel switches into a low conversion gain, low-sensitivity mode. The variable conversion gain is implemented by connecting a variable capacitive load in parallel with the photodiode of the image sensor pixel. When the incident light intensity exceeds a certain threshold, the variable capacitive load is increased to allow the photodiode to absorb more light. Likewise, the variable capacitive load is decreased when the incident light intensity is below a certain threshold.
