Physics question regarding optics.

[Hulk]

Hi, next week I'm starting a unit on optics with my high school physics class.

I know that as the aperature is increased in a camera (smaller opening in front of the lens) the depth of field is increased (more foreground and background is in focus).

How can I demonstrate this with a ray diagram? Or explain in terms of physics, not just what happens.

If you aren't a physics expert please don't respond. I understand what happens I'm just not sure EXACTLY why.

 

[Mday]

<< I know that as the aperature is increased in a camera (smaller opening in front of the lens) the depth of field is increased (more foreground and background is in focus). >>



that's not right actually... http://www.ces.ncsu.edu/depts/it/itaids/factsheets/digcamera/DC-002.shtml

in high school physics, you don't deal with aperature... you deal with focal lengths and properties of certain geometric surfaces... as in parabolas, ellipses...

focusing is mostly done by moving actual lenses... that is, by moving a lens, you move the focal point of that lens, so the defraction of the light is focused into a larger or smaller image on some screen.

with respect to the aperature, having more light available is not discussed...

 

[phatstyl]

hmmmm i forget so fast