Custom f-stop entry
Type any f-number for unusual or vintage lenses.
Where to find it
Equipment tab Lenses Add Custom Lens, or Viewfinder Aperture chip Custom
Summary
Type an arbitrary f-number for lenses that do not match the standard click-stop scale: vintage uncoated optics, projection lenses, Petzval revivals, soft-focus lenses with f/4.5 or f/6.3 maxima.
How it works
When to use it
Anytime your lens does not land on a standard stop. A 50mm f/0.75 prototype, a 105mm f/4.5 vintage portrait lens, a 300mm f/6.3 mirror lens; type the actual maximum aperture and the meter will use it directly.
How it stores
Each custom f-number you type goes into customApertures and persists with the lens entry. You can then pick it back up like any standard chip on the next session.
Pairs with custom lens entries
Custom apertures are most useful when paired with a custom lens spec in Equipment. The lens carries its own maximum aperture, focal length, and (optionally) hasBulb, so the meter solves around your real glass instead of approximating to the nearest standard stop.
Decimal precision
Type values to one or two decimals; the math layer treats f-numbers as continuous doubles, not enum constants. f/3.7, f/4.3, and f/9.1 are all valid inputs.