Apertia · Library
What can a focus plan change when the phone aperture is fixed?
On Apertia's iPhone main-camera preset every setting snaps to f/1.78; a 7 mm plan from 1 m to infinity needs f/3.1, so the planner proposes 2 frames instead.
When the aperture cannot change
The iPhone main-camera preset models the 48 MP main camera of iPhone 15 Pro to 17 Pro: a 9.8 × 7.3 mm sensor, a circle of confusion of 0.008 mm and a fixed f/1.78. In the calculator any other aperture snaps back to f/1.78, and the screen says the aperture is fixed. Depth can only change through focus distance and focal length.
The shot planner still solves for the exact f-number your near and far points need. If that number is at or below 1.78, one frame at f/1.78 works and the plan gives its focus distance. If it is larger, rounding is impossible, so the plan proposes a focus stack at f/1.78 instead.
Worked example
For the stated phone preset, 6.86 mm focal length and 500–1500 mm target range, the continuous requirement is about f/4.032. The assumed fixed opening is f/1.78, so it cannot simply be rounded to a selectable f/4 setting.
- Continuous requirement
- 4.03246
- Assumed fixed f-number
- 1.78
- Stacking required by this plan
- Yes
Plan with a fixed opening
- Choose the iPhone main camera preset and the focal length you use, such as 7 mm.
- In Shot plan, enter the nearest and farthest sharp points; use Infinity for a distant horizon.
- Read whether the result is one frame or a stack at f/1.78.
- For a stack, focus at each listed distance in turn without moving the phone.
- Check the plan with the camera mode you will actually use, since other lenses or crops change the setup.
Worked example: 7 mm, two requests
With 7 mm, asking for 3000 mm to infinity needs only f/1.024, so a single frame at f/1.78 focused at about 5993 mm covers it. Asking for 1000 mm to infinity needs f/3.095, which the fixed lens cannot reach. The plan proposes 2 frames at f/1.78: the first focused at 1400 mm covers 1000–2339 mm, the second at 3455 mm covers 1731 mm to infinity, so the two zones overlap.
- 3000 mm – infinity
- needs f/1.024 · one frame at 5993 mm
- 1000 mm – infinity
- needs f/3.095 · stack
- Frame 1
- 1400 mm (1000–2339 mm)
- Frame 2
- 3455 mm (1731 mm – infinity)
Common mistakes
- Expecting the planner to suggest f/4 on a phone; the preset never changes the aperture.
- Using the preset for the ultra-wide or telephoto camera, which have different sensors.
- Assuming portrait mode follows the thin-lens result; its blur is added by software.
- Moving the phone between stack frames, which breaks the alignment the plan assumes.
Scope of the preset
The preset values come from published specifications of one camera family and are a planning assumption, not a check of your phone or its current mode. The DOFMaster equations listed below are the thin-lens relations the planner applies to it.