Question

Makers of cameras often use pixel count as an indicator of quality, and add sensors with more and more pixels. But the number of pixels is only one determinant of image quality. If the width of the central maximum of a diffraction pattern is larger than twice the spacing between the pixels, then packing the pixels more densely won't change the image quality. It's hard to get a camera with good optical quality in a smartphone; the lens must be small, so diffraction will be an issue. One smartphone manufacturer includes a camera with 20.7 MP, which sounds very good. But let's look at the numbers: The distance between the pixels is 1.2 μm; the focal length of the lens is 4.8 mm, with a 2.2-mm -diameter aperture.

Part A For 600 nm light, what is the width of the central maximum?

Answer 1

Part A: The width of the central maximum is given by, 1.22nf -9 1.22 600 nm 4.8 mm nm mm | 1 um 10° m 3.2x10 m^^