I placed this in quantum department but since no comments came either it belongs here or is too trivial. Please comment. MY POST IN QUANTUM PH. FORUM ... " This problem I encountered in my photography forum. A new model of camera comes out with a much higher megapixel sensor (Nikon D800, 36mpix). I argue that such sensor will need new lenses to be meaningful. Others claim that a given lens performance (here resolution) is always utilized by a new higher resolution sensor. They call up Fourier transforms, modulation transfer functions etc. I am not an engineer, more of an amateur philosopher. To me it smells of Zeno paradox (a "quantum Zeno effect" ?). There sure must be a limit on the amount of information a new ever improving recording medium (sensor) can extract from the same old lens? Or not? Or does this issue belong to classical physics? I mean, in my mind I see a lemon running out of juice at some point of the squeeze. Isn't the information coming through any given lens limited then? No more photons to be converted into electrons? On one hand it's the issue of quantum efficiency of the CMOS sensor, but also the physical information limit of the light field? So are those Fourier transforms of MTFs accurate descriptions or we are at the point where technology stumbles on quanta? OPONENT'S ORIGINAL POST IN PHOTO FORUM "... As I wrote the formula is an approximation. For accurate results one would need to multiply the MTFs by means of Fourier transforms. Every image will show more resolution on the D800 with any lens at any aperture than on previous Nikon's. The resolution of a system is a function of the resolution of it's parts, not only a single component. The resolution of a lens plus sensor system can be approximated by: 1/Total resolution = 1/lens resolution + 1/sensor resolution. Or Total resolution = (lens resolution)x(sensor resolution) / [ (lens resolution) + (sensor resolution) ]. ".... MY POSITION IN PHOTO FORUM "Resolution figures are meaningless without accompanying contrast data. One has to put somewhere the cutoff line: what is acceptable. In cinematography Zeiss Master Prime delivering 70lp/mm at 70% contrast is the standard bearer (at 25k U$ and several pounds) In photography I am willing to accept 50% contrast as a minimum performance measure. If somebody wants to go down to MTF 25 or even 10--his choice. He will be able to point to "extra resolution" on his cranked up monitor viewed at 100%. The concept of a lens delivering an ever-increasing stream of visual information as the recording medium becomes more and more capable, is philosophically intriguing, to say the least. A "quantum Zeno effect" of sorts." OPPONENT'S ANSWER IN PHOTO FORUM "If you would have read the thread I linked to further, you would have found that the approximation is based on multiplications of MTFs by means of Fourier transforms, You can pick any frequency (resolution) you want. Higher frequencies are generally used as a measure of resolution and lower as contrast. The approximate formula is still valid and serves as a good first approximation to explain the principles of what can be expected for a system of lens plus sensor.The optical perfomance of a system of two components (lens and sensor) is not determined just by a single component but by both." You can think of it as two MTFs stacked on top of each others."