Why does the aperture setting affect DoF?

jbswear

Since technique is something you learn from trial and error (and lots of error on my part!) I mainly ask questions concerning the physical aspect of shooting.

Can anybody explain to me why changing the amount of light entering the lens affects how much of the field is in focus? I've a good grasp of physics and light's tendencies, but don't know why this happens.

Thanks!

mods--if this needs to be moved, please feel free!

Andy

http://en.wikipedia.org/wiki/Aperture

jbswear

Andy wrote:

http://en.wikipedia.org/wiki/Aperture

Doesn't explain the 'why' of it all...I understand the concept of different aperture settings (then again, putting them into practice boggles this beginner) and when to use them (sometimes) but the rest eludes me.

ziggy53

A fairly good explanation is here:

http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/950/depth-of-field.html

ziggy53

erich6

There's also this discussion in the Technical forum:

http://www.dgrin.com/showthread.php?t=11015

Erich

Sledhed

Play with the settings on this virtual camera and you'll get a pretty good idea how SS and aperture effect each other and the dof.

http://www.photonhead.com/simcam/shutteraperture.php

ysr612

ziggy53 wrote:

A fairly good explanation is here:

http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/950/depth-of-field.html

ziggy53

that one was good just like the wave chapter in basic physics.