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This is physically impossible. Without active amplification, the luminance of the image can not be more than the luminance of the subject. Otherwise you would be violating the second law of thermodynamics. If you try to focus the sun rays on a black body, it can get really hot, but not hotter than the surface of the sun itself. For a mathematical proof, read ...


11

There are two hard limits on how fast a lens can be: The first is a thermodynamic limit. If you could make a lens arbitrarily fast, then you could point it to the sun and use it to heat your sensor (not a good idea). If you then get your sensor hotter than the surface of the Sun, you are violating the second law of thermodynamics. This sets a hard limit at ...



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