Depth of field

[Julius]

I have a Canon 1000d with a depth of field button, however the instruction manual is very fague on how to use it.

When I look the lens and press the dof button sometimes the bottom of field looks darker.

can any one share some light on this area?

[timo2]

When you press the DOF button, the aperture closes to whatever it is set to, hence the screen darkening; it’s always more apparent in the darker areas and not so obvious in the lighter sky.

[Peter Ryan]

Hi Julius and welcome to CiC.

Tim is correct. With DSLRs you view the image Through The Lens (TTL). To get as much light as possible to see the shot the camera leaves the aperture completely open. Only when you come to push the shutter release does it close down to the aperture you set, which can be much darker. When you push the DOF button you are looking at it the same way as the camera will take the shot. Sometimes you need to let your eyes aclimatise to the darker light to see the DOF effect.

[Nass]

When you actually take a shot at F22 you'll get more depth of field than if you took it at f5.6. A preview will show in the shot that's actually taken. Depth of field meaning 'area that looks in focus'. When you're just looking through the viewfinder and you havn't taken the shot yet you don't see the depth of field clearly because actually your lens is wide open.