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- What exactly determines depth of field? 4 answers
What does the term depth of field mean?
How is it determined and how can it be changed?
Is it related to the aperture?
Depth of field is the amount of the image/subject that is in acceptable focus. Depth of field varies with subject distance and aperture. A larger aperture (lower f numbers) gives shallower depth of field with a given lens. A narrower aperture gives deeper depth of field with that same lens.
Old-school cameras provide a depth of field scale on the lens so that you can tell how much of the subject will be in focus based upon your aperture and focus setting. Modern cameras have dispensed with this important (IMO) feature for the most part.
If you are shooting an SLR, you can see the effect of a given aperture/focus distance by using the depth of field preview button/lever (if your camera has one).
I have done a video over here that covers depth of field, and demonstrates it using a classic lens' depth of field scale:
From Cambridge in Colour:
See the link for all the details, but in a nutshell: