Design Nomenclature / Light & Optics
Depth of field
Also called DOF
- Light & Optics
- Composition
- 2D & 3D
The band of subject distances rendering acceptably sharp — where the blur circle stays under a chosen threshold. Exactly one plane is truly in focus; everything else is a compromise about how much unsharpness passes. It narrows with wider apertures, longer lenses, and closer subjects.
In practice
Shallow depth of field is a compositional decision — it says what to look at. Treating it as a quality marker is the most reliable tell of a beginner.
Not to be confused with
- BokehThe character of the out-of-focus rendering — how a blur circle is filled, whether its edge goes bright or soft, whether it turns to onion rings or cats' eyes toward the corners. A judgement about quality, set by the lens's aberration correction and the shape of its iris.
- Circle of confusionThe disc a point source projects onto the sensor when it sits away from the focus plane. Depth of field is entirely a decision about how large this may grow before it reads as unsharp — a threshold set by print size, viewing distance, and eyesight, not by physics.