Apertia · Library
Plan a shot
Say what must be sharp; get the focus distance and f-stop.
Start with the zone you want in focus
Enter the nearest target and either a finite far target or infinity, measured from the sensor plane. The reverse planner calculates a focus distance and continuous aperture requirement, then compares it with a native aperture-stop choice.
A rounded stop and a continuous requirement are separate outputs. Inspect the range-coverage state instead of assuming that a suggested stop covers every requested distance. When one exposure is insufficient in the model, the result makes the stacking requirement explicit.
Use the result as a plan
The calculation uses the same thin-lens and circle-of-confusion assumptions as the depth-of-field model. It does not choose a shutter speed, predict motion or guarantee a real lens’s resolving performance.
Method and reference context
Say what must be sharp; get the focus distance and f-stop.
A thin-lens plan using distances from the sensor plane. Real lens behaviour, focus breathing and computational photography are outside this model.
Results
Example calculation
Plan a shot: worked out from the values already filled in the form above.
Inputs
- Sensor: Full frame
- Focal length: 50
- Nearest sharp point: 1,500
- Far target: Finite distance
- Farthest sharp point: 6,000
Result
- Focus distance: 2,381.3512
- Continuous f-number requirement: 22.2302768
- Model f-stop selection: 32
- Model recommends stacking: Yes
- Requested range covered: Yes
- Aperture: 11
- Requested near target (mm): 1,500
- Finite far target (mm): 6,000
- Focus distance: 1,830.63725 · Near: 1,500 · Far: 2,356.8543 · Far limit is infinity: No
- Focus distance: 3,344.14818 · Near: 2,356.8543 · Far: 5,809.69027 · Far limit is infinity: No
- Focus distance: 7,676.08758 · Near: 3,863.20879 · Far: Infinity · Far limit is infinity: Yes
Related tools
Focus-stack plan · Geometric blur diameter (mm) · Horizontal angle of view (°)