lens_file_read — OPTICS lensfile op

• Data kinds: none → table (an op determined by its arguments alone — it takes no image or data input)

• Call: import fullseye as fs; fs.ledger.lens_file_read(source=None, allow_partial: 'bool' = False, glass_dir=None) -> 'dict' (to call the implementation directly, import lensfile; lensfile.lens_file_read(source=None, allow_partial: 'bool' = False, glass_dir=None) -> 'dict'; from the registry, opsoptics.get("lens_file_read"))

Usage

Read a .zmx sequential lens prescription into a Fullseye prescription (table).

*source* is a file path, the file's text, its bytes, or None for the bundled example ZMX_EXAMPLE (a Cooke triplet, f ≈ 50 mm, f/5).

Encodings: UTF-16 with a byte-order mark (what current design programs save), UTF-16 without one (detected from the NUL pattern), UTF-8 and Latin-1. *glass_dir* (or the environment variable FULLSEYE_GLASS_DIR) is a directory of .agf glass catalogues searched before the built-in material table. *allow_partial* admits the approximations listed in the module help and marks the result approximate=True; without it they are refused.

Returns {"system", "name", "notes", "unit", "aperture", "field_type", "fields", "wavelengths", "primary", "surfaces", "solves", "approximate", "encoding", "source", "report"}: system is a ready raytrace.lens_system at the primary wavelength (field 0 — pick a field

with lens_file_system), fields are {"x", "y", "weight", "field"} with field the radial value raytrace takes (degrees or mm), surfaces is the file-level model (curvatures in 1/mm, signed thicknesses as the file stores them, glasses, apertures, solves) that lens_file_write writes back, and report classifies every keyword as read / ignored / unsupported (see lens_file_report).

A file with an MNUM table (more than one configuration) is read into the active configuration plus system["configurations"], a list with one sparse override dict per configuration (see lensconfig); the result also carries n_configurations and active_configuration (0-based).

A file with COORDBRK surfaces is read into a raytrace3d.noncoaxial_system (noncoaxial is True, system is that table, each field's field is the pair (x, y), pupil holds the entrance-pupil radius, stop radius and effective focal length found with real axial rays, surface_records[j] the tracer records of file surface j); the conventions are in the module help.

Example::

p = lens_file_read("triplet.zmx")

RT.paraxial_trace(p["system"])["efl"]

sysf = lens_file_system(p, field_index=2) # the 20-degree field

RT.spot_stats(sysf)

q = lens_file_read("folded.zmx") # tilts / decentres: a non-coaxial system

raytrace3d.noncoaxial_spot(lens_file_system(q, field_index=1))["rms_radius"]

Family-wide input contract (fail-closed)

Every optics op validates its input before computing (nothing slips through silently):

• Units are baked into the argument name — _mm / _um / _deg / _mrad. Confusing mm with µm does not crash; it yields a plausible-looking wrong answer, so the name prevents it. Nothing here guesses the unit from the magnitude.

• Strings raise ValueError — float('50') succeeds, so an unparsed configuration value would slip through as a length (measured: thin_lens('50', '200') returned a plausible 66.667 mm). bool is refused too, as the implicit promotion True == 1.

• complex / masked arrays raise ValueError (real-valued slots only; silently dropping the imaginary part or peeling off the mask is refused). NaN/Inf raises ValueError on every input.

• Division by zero and its relatives are refused by name: focal length 0, radius of curvature 0, refractive index <= 0, a fully opaque aperture (all zeros, so the normalisation is 0/0), a PSF whose sum is <= 0, a Stokes vector with S0 = 0, and an object sitting at the front focal point (the image is at infinity).

• Only two ops return a non-finite value, and both state it as a contract: depth_of_field returns far_mm = inf beyond the hyperfocal distance (that is what the hyperfocal distance means), and gaussian_beam returns wavefront_radius_mm = inf at the waist (the radius of curvature of a plane wavefront). Both also return a finite companion (far_is_infinite / curvature_per_mm). Any other silent NaN/Inf is detected internally and raises ValueError — "float64 overflowed" and "the answer is infinite" are different claims, so the first is never returned wearing the face of the second.

• Size caps: generated grids are capped by optics.MAX_GRID (4096); supplied fields/PSFs/apertures by optics.MAX_FIELD_ELEMENTS (2^24); ABCD element chains by optics.MAX_SYSTEM_ELEMENTS (1024); Zernike by MAX_ZERNIKE_TERMS (512) / MAX_ZERNIKE_ORDER (40) / MAX_ZERNIKE_BASIS (2^25). This closes, fail-closed, the paths where a small argument triggers a huge internal allocation (measured: n_max=40 × 4096² needs 108 GB).

• Physically impossible states are refused too: a Stokes vector with degree of polarisation > 1, negative transmittance, negative intensity, and invalid Zernike indices such as n-|m| odd.

Detailed usage guide

• optics_imaging family guide

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• optical_design_metrics — py -3.11 examples/optical_design_metrics.py

• poc_lens_file_roundtrip — py -3.11 examples/poc_lens_file_roundtrip.py

• poc_zoom_configurations — py -3.11 examples/poc_zoom_configurations.py

Ops the type connects to (they accept table as input)

abcd_matrix · wavefront_stats · sfr_from_edge · paraxial_trace · seidel_coefficients · spot_stats · tolerance_analysis · wavefront_from_opd

Same category (lensfile)

lens_file_system · lens_file_write · lens_file_report


*Provenance: lensfile.py — OPTICS operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.