I think the question hints towards a basic misunderstanding that most have regarding light, and respectfully offered to many: the way that light and information is passed is highly glossed over. Any device that can "see" can only interact with incident light, light that falls onto or into the device (including our eyes).
All possible information contained within the light can then be accessed, within the confines of the device. Kind of like a computer hard drive if you will. Depending on how you reach into that information will determine what information you read. Current discussion here relates to how the lease will change focal point, but that is one only one dimension to the information.
The changing foci redirects the peering into the incident light's store of information, and that is what zoom is doing.
I realize this may sound a tad bizarre to some, but one day the world will better understand light.