Source: https://guthlabs.ai/docs/instruments/diffraction-limit-optimal-aperture-calculator/

instrument / verified-clean

# Diffraction Limit / Optimal Aperture Calculator

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/diffraction-limit-optimal-aperture-calculator/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/diffraction-limit-optimal-aperture-calculator/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/diffraction-limit-optimal-aperture-calculator/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/diffraction-limit-optimal-aperture-calculator/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Audio, Music, Photography & Color

**Tranche**: tranche-5

**Evidence ID**: t5-077

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The honest-label warning about physical-optics approximation and lens quality is appropriate but incomplete. The product must disclose the explicit diffraction criterion and resolve the contradiction between N=pixelPitch/(1.22λ) and Airy diameter=2.44λN before claiming a standard diffraction-limit calculation.

### Formula and scope findings

- The stated formula N≈pixelPitch/(1.22*λ) is not consistent with the stated Airy-disk diameter formula when the criterion is that the Airy disk diameter equals one pixel. Substitution gives Airy diameter=2.44*λ*(pixelPitch/(1.22*λ))=2*pixelPitch. Under the one-pixel Airy-diameter criterion, the corresponding formula is N≈pixelPitch/(2.44*λ).

- The phrase "begins to visibly limit resolution" does not define a unique optical criterion. Depending on the chosen criterion, the relevant comparison may involve Airy-disk diameter, Airy radius, pixel pitch, or sensor Nyquist frequency; the criterion must be stated explicitly.

- The sensor megapixels-and-size input path does not specify whether size means active width and height, diagonal, or nominal format size, nor does it specify the aspect ratio and active-area assumptions needed to derive pixel pitch.

### Unit assumptions

- Pixel pitch and wavelength must use the same length unit; with λ=0.00055 mm, pixel pitch must be supplied in millimetres or converted to millimetres.

- The default λ≈0.00055 mm means 550 nm monochromatic green light; real scenes and sensors respond over a wavelength band.

- For megapixel-plus-size calculations, the sensor dimensions are assumed to be active imaging width and height in millimetres, pixels are square, and the stated megapixel count is the active pixel count.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The specification does not state validation behavior for zero megapixels, zero or negative pixel pitch, or other nonphysical inputs. Zero megapixels creates a division-by-zero during derived pixel-pitch calculation, while negative pixel pitch produces sign-dependent and physically invalid outputs unless explicitly rejected or converted to an absolute magnitude.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "manual_pixel_pitch_mm": 0.004,
    "wavelength_mm": 0.00055
  },
  "expected_outputs": {
    "diffraction_limited_f_number": 5.961252,
    "airy_disk_diameter_mm": 0.008
  },
  "working": "1.22*λ = 1.22*0.00055 = 0.000671 mm. N = 0.004/0.000671 = 5.961252. Airy diameter = 2.44*0.00055*5.961252 = 0.008000 mm, equivalently 2*0.004 = 0.008000 mm."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche5/tranche5-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`