A scenario:
Two photographs are taken using a digital camera. One photograph is taken with a shutter speed of 1/30, the other with a shutter speed of 1/60. The images are output as 8 bits per channel, RGB files. If the value in channel C, at co-ordinates X,Y of the first photograph is 128, what should the value be in C,X,Y of the second photograph and why?
Simple logic suggests that, assuming the response curve of the camera is linear, the second value should be half that of the first, since the amount of light hitting the sensor is halved, but this appears not to be the case. Instead, the value in C,X,Y of the first photograph appears to be approximately equal to the value in C,X,Y of the second photograph, multiplied by the square root of two. Why?
Math/Photography: How does changing the shutter speed affect the output value?
I wouldn't know, but the guy in this article knows his ****.
