They are using megapixel to mean "modulation transfer function": https://en.wikipedia.org/wiki/Optical_transfer_function https://en.wikipedia.org/wiki/Optical_t

They are using megapixel to mean "modulation transfer function": https://en.wikipedia.org/wiki/Optical_transfer_function https://en.wikipedia.org/wiki/Optical_transfer_function As many of the replies state, it doesn't make sense. I think the original author knew of the idea, but not the word. Now you can know the word :)