1. An electronic camera for producing an output image of a scene from a captured image signal, said electronic camera comprising: a first imaging stage comprising a first image sensor for generating a first sensor output, a first lens for forming a first image of the scene on the first image sensor, and a first lens focus adjuster for adjusting focus of the first lens responsive to a first focus detection signal; a second imaging stage comprising a second image sensor for generating a second sensor output, a second lens for forming a second image of the scene on the second image sensor, and a second lens focus adjuster for adjusting focus of the second lens responsive to a second focus detection signal; and a processing stage for either (a) selecting the sensor output from the first imaging stage as the captured image signal and using the sensor output from the second imaging stage to generate the first focus detection signal for the selected imaging stage or (b) selecting the sensor output from the second imaging stage as the captured image signal and using the sensor output from the first imaging stage to generate the second focus detection signal for the selected imaging stage, whereby the focus detection signal is applied to the lens focus adjuster of the selected imaging stage in order to adjust the focus of the image providing the sensor output for the captured image signal.