If the Focal point is within the Depth of field it will be in focus. The area within the depth of field will be “acceptably sharp” and outside of that will be blurry. A wider depth of field means the falloff from focus to acceptably sharp to blurry is more gradual and more of the image will appear in focus.
| Factor | Increases DOF | Decreases DOF |
|---|---|---|
| Aperture | Higher f-number | Lower f-number |
| Focal Length | Shorter Focal length | Longer Focal length |
| Subject Distance | Greater distance from the camera | Closer distance to the camera |
If I’m shooting a miniature and PhotoPills estimates a 2cm DOF and the miniature is 5cm wide, then it will not be in focus. I can either increase aperture, decrease focal length, or move the camera further away. That may not get me the framing I want yet any shortening of distance to counteract the shorter focal length will again decrease DOF. For most cases such precision is not required. For miniatures a tape measure is necessary.