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)