3 ms·
More specifically the f/ number relates to the size of the entrance pupil (the optical image of the physical aperture stop, as seen through the front of the len
by roelschroeven 5y ago
More specifically the f/ number relates to the size of the entrance pupil (the optical image of the physical aperture stop, as seen through the front of the lens) rather than the size of the physical aperture. Depending on the construction of the lens and where in the lens the aperture is located, the two can differ quite a lot.