ImageReasonFocus, Depth of Field, and Macro
How much did my frame actually change during that focus pull?
Enter your measured far-focus and near-focus frame coverage to see the framing change and the crop needed to match, a measurement of your test, not a lens-behaviour prediction.
Answer
Calculate a result to see whether this crosses your stated tolerance.
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Calculate to see the two frame rectangles.
| Sample | Coverage | Change vs. far |
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Calculate a result to generate a copyable plan.
A framing measurement, not a lens label
Focus breathing is best handled as a framing measurement, not a label attached to a lens. If the same composition becomes tighter or wider through a focus pull, the question is whether that change exceeds the tolerance for the shot. Measuring the actual frame at two distances makes the crop or composition margin visible without guessing how a particular lens behaves.
If a fixed reference target spans four metres across the far-focus frame and 3.6m at near focus, the near frame is 10 percent tighter. Matching that tighter frame from the wider one would need roughly a 10 percent linear crop. Whether that matters depends on the delivery framing and the focus move. Repeat the test with the camera locked, then decide whether to compose wider, accept the change, or choose another lens.
This is a planning calculation, not a certification. Confirm the relevant camera, lens, card, printer, contract, location, or workflow constraint in the real setup before relying on the result.
Make one controlled test with the important variable held constant. Inspect the subject detail, motion, highlights, and intended output, then adjust the setting that protects the priority you named.
FAQ
- Can this tell me whether my lens breathes?
- It calculates the change you measure in a controlled test. It does not predict a lens's behaviour or judge whether it is acceptable.
- Is this a guarantee?
- No. The result is bounded by the inputs and assumptions shown on the page. It is designed to support a better next decision, not replace a test, measurement, proof, or professional judgement where one is needed.