I understand that a small aperture (large aperture number eg.
F/22) means large depth of field. It is simple to undersand that
small aperture size means, less light is allowed into the camera
sensor. If less light is allowed how is the large depth of field
is acheived?. I always believed that "Large" means you need more
light, but in this case, if aperture is small, large depth of
field is achieved. Could someone please help me understand this
from form technical perspective. I have seen many threads
related to somewhat same question, but I don't think I have got
much help, so I am posting this question (I own a D90)