A method of outputting a signal from a pixel photodiode in response to incident light thereon, the pixel photodiode including a floating diffusion region and an overflow diffusion region, the method comprising the steps of:- resetting the pixel photodiode during readout of a previous frame; integrating electrons accumulated on the pixel photodiode in a signal integration phase; sampling a reset level value ( r A) corresponding to offset and noise for the floating diffusion region; transferring electrons from the pixel photodiode to the floating diffusion region; receiving electrons in the floating diffusion region from the pixel photodiode; converting the received electrons in the floating diffusion region into a first charge value corresponding to the received electrons, the first charge value corresponding to a first output signal ( S A); using the reset level value ( r A) to compensate for at least one of: noise and offset in the first output signal ( S A); the method characterised by the steps of: comparing the result of the compensation with a predetermined threshold; if the result of the comparison is below the predetermined threshold, reading out the first output signal ( S A), corresponding to the first charge value, from the floating diffusion region at a first sensitivity level; if the result of the comparison is above the predetermined threshold, transferring electrons from the floating diffusion region to the overflow diffusion region; storing the electrons received in the overflow diffusion region and converting them into a second charge value corresponding to the transferred electrons; re-distributing the first and second charge values over both the floating diffusion region and the overflow diffusion region; converting the re-distributed charge value obtained by said re-distribution of the first and second charge values on the combined floating diffusion and overflow diffusion regions (140, 170) into a second output signal ( S A + B); and reading out the second output signal ( S A + B), corresponding to the re-distributed charge value, from the floating diffusion region at a second sensitivity level, the second sensitivity level being lower than the first sensitivity level. resetting the pixel photodiode during readout of a previous frame; integrating electrons accumulated on the pixel photodiode in a signal integration phase; sampling a reset level value ( r A) corresponding to offset and noise for the floating diffusion region; transferring electrons from the pixel photodiode to the floating diffusion region; receiving electrons in the floating diffusion region from the pixel photodiode; converting the received electrons in the floating diffusion region into a first charge value corresponding to the received electrons, the first charge value corresponding to a first output signal ( S A); using the reset level value ( r A) to compensate for at least one of: noise and offset in the first output signal ( S A); the method characterised by the steps of: comparing the result of the compensation with a predetermined threshold; if the result of the comparison is below the predetermined threshold, reading out the first output signal ( S A), corresponding to the first charge value, from the floating diffusion region at a first sensitivity level; if the result of the comparison is above the predetermined threshold, transferring electrons from the floating diffusion region to the overflow diffusion region; storing the electrons received in the overflow diffusion region and converting them into a second charge value corresponding to the transferred electrons; re-distributing the first and second charge values over both the floating diffusion region and the overflow diffusion region; converting the re-distributed charge value obtained by said re-distribution of the first and second charge values on the combined floating diffusion and overflow diffusion regions (140, 170) into a second output signal ( S A + B); and reading out the second output signal ( S A + B), corresponding to the re-distributed charge value, from the floating diffusion region at a second sensitivity level, the second sensitivity level being lower than the first sensitivity level. comparing the result of the compensation with a predetermined threshold; if the result of the comparison is below the predetermined threshold, reading out the first output signal ( S A), corresponding to the first charge value, from the floating diffusion region at a first sensitivity level; if the result of the comparison is above the predetermined threshold, transferring electrons from the floating diffusion region to the overflow diffusion region; storing the electrons received in the overflow diffusion region and converting them into a second charge value corresponding to the transferred electrons; re-distributing the first and second charge values over both the floating diffusion region and the overflow diffusion region; converting the re-distributed charge value obtained by said re-distribution of the first and second charge values on the combined floating diffusion and overflow diffusion regions (140, 170) into a second output signal ( S A + B); and reading out the second output signal ( S A + B), corresponding to the re-distributed charge value, from the floating diffusion region at a second sensitivity level, the second sensitivity level being lower than the first sensitivity level.