Lens Depth of Field Calculator
Depth of field is the range around the focused subject distance that falls within a chosen sharpness criterion. Focal length, aperture and focus distance combine with an assumed circle of confusion to estimate that range.
How to use this calculator
- Enter physical focal length, f-number, focus distance and a circle-of-confusion value appropriate to your format.
- Check that units, denominator definitions and time periods are consistent before comparing scenarios.
- Run a second scenario when an assumption is uncertain.
Formula used by lens depth of field calculator calculator
Hyperfocal distance H ≈ f² / (N × circle of confusion) + f; near/far limits use a simplified thin-lens depth-of-field relationship.
- Hyperfocal distance H ≈ f² / (N × circle of confusion) + f; near/far limits use a simplified thin-lens depth-of-field relationship.
- Real lens focus breathing, pupil magnification, sensor format and display conditions can change perceived depth of field. The tool uses a simplified thin-lens model.
- The tool performs arithmetic on the values entered and does not validate assumptions against outside records.
Worked examples
Worked example
50 mm lens at f/2.8 focused at 3 m, using a 0.03 mm circle of confusion.
The hyperfocal distance is approximately 29.9 m; the near and far limits are calculated from the thin-lens depth-of-field relations.
The near and far focus limits are estimates for the entered optical assumptions.
Understanding the result
Depth of field is the range around the focused subject distance that falls within a chosen sharpness criterion. Focal length, aperture and focus distance combine with an assumed circle of confusion to estimate that range.
Real lens focus breathing, pupil magnification, sensor format and display conditions can change perceived depth of field. The tool uses a simplified thin-lens model.
Important notes
Real lens focus breathing, pupil magnification, sensor format and display conditions can change perceived depth of field. The tool uses a simplified thin-lens model.
Treat this output as an estimate tied to the stated inputs. For regulated, safety-critical, tax or professional decisions, verify applicable official guidance and specifications.
Frequently asked questions
Why ask for circle of confusion?
It defines the acceptable blur criterion used to estimate depth of field.
Does this predict autofocus accuracy?
No. It estimates a geometric sharpness range, not autofocus or lens performance.
How should I interpret the result?
Real lens focus breathing, pupil magnification, sensor format and display conditions can change perceived depth of field. The tool uses a simplified thin-lens model.
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Related explanations
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.