Apertia · Library
Why should infinity remain a state rather than a very large distance?
A 50 mm f/8 full-frame focus at 10516.907 mm gives a 5283.573 mm near limit and an unbounded far limit; keep that far side marked as infinity.
When the far limit becomes unbounded
Apertia computes the far limit on the lens side as u × (H − f) ÷ (H − u), with H = f² ÷ (N × c) + f. When u reaches H the denominator falls to zero, and for any u at or beyond H the app stores the far limit as infinity and shows the Infinity label instead of a number. The total depth of field is then infinite as well, so no finite width exists to report.
The hyperfocal distance shown in the app is H plus its image distance, measured from the sensor plane. Focusing there gives the widest interval that still ends at infinity, and the hyperfocal table explains this as everything from about half that distance to infinity being within the chosen blur tolerance.
Worked example
At infinity focus, the 50 mm full-frame model at f/8 and a 0.030 mm tolerance places the near boundary at about 10466.667 mm. The null fields represent the unbounded interval, not a failed conversion to zero.
- Near boundary (mm)
- 10466.666667
- Far boundary
- Unbounded
- Far side is unbounded
- Yes
- Total width
- No finite width
Keep the state in a saved plan
- Read the far limit label first: Infinity means the model places no far boundary.
- Record the near limit as a number with its unit.
- Leave the total width empty rather than subtracting from an invented distance.
- In the shot planner, switch the farthest sharp point to Infinity instead of typing a large number.
Worked example: three focus settings at f/8
For 50 mm at f/8 with the 0.030 mm full-frame circle of confusion, H = 2500 ÷ 0.24 + 50 = 10466.667 mm, and the hyperfocal distance from the sensor plane is 10516.907 mm. Focused there, the near limit is 5283.573 mm and the far limit is unbounded. Focused at infinity, the near limit moves out to 10466.667 mm, so about 5.2 m of foreground is lost for no gain at the far end. Focused at 5000 mm, the interval is finite again: 3416.706 to 9395.359 mm, a total of 5978.653 mm.
- Focus at 10516.907 mm
- 5283.573 mm to Infinity
- Focus at infinity
- 10466.667 mm to Infinity
- Focus at 5000 mm
- 3416.706 to 9395.359 mm
Common mistakes
- Replacing infinity with one million millimetres and then reporting a total depth of field of nearly a kilometre.
- Focusing at infinity for a landscape and losing half of the near range the hyperfocal setting would keep.
- Reading an unbounded far limit as unlimited detail in distant objects.
Interpretation limit
An infinite far limit only means the geometric blur stays inside the chosen tolerance for every farther distance. Diffraction, atmospheric haze and lens resolution still limit distant detail. The DOFMaster equations listed below define the same hyperfocal relation.