Question

Explain why reducing the size of U, V , and ? may not have significant effect on the quality of an image.

Answer 1

Having looked at what happens with cameras and crops made from the same sized pixels, what happens if we have differently sized pixels? Aren't small pixels worse because they're receiving less light? The answer is: not by as much as you'd think (if at all). Here we're talking about the relatively large sensors typically used in interchangeable lens cameras - pixel size can play more of a role at the extremes of small pixel design encountered in tiny smartphone sensors.

The pixels in large sensors are many times*4 the size of the cutting-edge ones used in smartphones, so aren't working anywhere near the limits of current design constraints. It's also reasonable to assume that sensor makers would try to avoid increasing the pixel count until they can make pixels with read noise that comes close to matching the performance of their existing sensors (read noise =1/?pixel increase factor), since better products are easier to sell.

Even if this 19% gap can't quite be bridged, the differences will be very subtle: in good light, where shot noise dominates, there'll be no difference if the two images are viewed at the same size. In the deep shadows or at high ISOs, where read noise begins to play more of a role, you will see at worst a 22% increase in the read noise contribution (and almost always less).