Sony ARWs record shading, lateral chromatic aberration and distortion as a camera setting plus a radial
table in the raw image IFD (0x7031-0x7037), with copies in the encrypted SR2SubIFD (0x797c-0x7982).
They are now decoded for every body that records them and carried through RawInfo and RawImage as
`lens_metadata.sony` (types in crates/raw/src/lens_metadata.rs, decoder in
crates/raw/src/vendor/arw_lens.rs):
- Raw-IFD fields are the ones the TIFF reader parsed, which is what the image itself uses. A scan of
the directory adds diagnostics only: repeated tags, and why an entry the reader skipped was dropped
(values outside the file, an unknown type, past the reader's limits). SR2SubIFD fields are read
from their first entry. Only the exact layouts are accepted: SHORT[1] or non-negative SSHORT[1]
settings, SSHORT[17] headed by 16 for shading and distortion, SSHORT[33] headed by 32 for CA.
Nothing is allocated from a count in the file.
- The raw IFD's copy wins. The SR2SubIFD copy fills in only for a tag the raw IFD lacks, never for a
malformed one, and the two copies' agreement is recorded.
- Settings keep their number and their documented meaning, Unknown(value) otherwise (never Off).
- Framing evidence (stored frame, Sony and default crops, reference rectangle, coding, 3:2) and a
per-component status. Only Applied components become opcodes.
Applied corrections are unchanged: the ILCE-7RM4A distortion conversion receives exactly the table it
received before, and no other body or component gains a correction. The ILCE-7CR distortion misses its
camera JPEG at 24 mm, and shading and CA semantics are not validated on any body; see
docs/sony-lens-corrections.md.
Locating the SR2SubIFD, now done for every ARW that has one, selects the SR2Private offset, length and
key with the TIFF reader's own rules, which lightcraft-tiff now exposes and builds its reader on
(directory_entries, entry_span, ParseOptions::budget_for, decode_value). Only each field's first value
is decoded, so the directory's other entries cost no memory sized by the file: a 16 MiB file whose
SR2Private holds eight fields aliasing it peaks at 37 kB. DirectoryEntries keeps its layout private,
and its positions() iterator uses checked arithmetic.
Tests: synthetic decoder tests; a differential test of the SR2Private selection against the TIFF
reader's in both byte orders (0 to 8,193 filler entries, unreadable and unusual first occurrences of
each field, a used-up value budget); a dhat peak-heap test; public-corpus checks against the values
ExifTool prints, with pinned and anchored SHA-256s (LIGHTCRAFT_CORPUS_REQUIRED=1 makes absent files
fail); and an opt-in local inventory check (crates/raw/tests/sony_lens_inventory.rs).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
docs/sony-ilce7rm6-lens-corrections.md records the three Sony tables, the
measured conventions with their residuals, the conversion to
WarpRectilinear and its fit gate, the model allowlist and how to extend
it, the measurement method, the verification and the limits.
Verified locally on 54 ILCE-7RM6 photos with four lenses. The corrected
render lines up with the camera JPEG within 0.679 px at 1440 px at the
corners and edge midpoints of the 33 measurable photos shot with
in-camera correction on (up to 17.3 px uncorrected). The 13 controls show
the model's own shift. Every fit passes the 0.25 px gate (margin 0.075).
Lateral CA stays within 0.3 px, but applied after demosaic it raises the
render's corner CA (rms 0.032 -> 0.052 px); the doc and tracker say so.
Its "Two conventions" section sets these conventions next to the
ILCE-7RM4A's (vendor::arw_lens, docs/sony-lens-corrections.md, #498):
on the 34 measurable ILCE-7RM6 photos that formula gives 1.429 / 0.319 px
(max / rms) against 0.596 / 0.143, failing only on the 24-70 GM II and
fitting the 100 mm and 200-600 better; no single unit fits every lens
under either, and what would settle it (Sony On/Off exports of a wide
zoom, more lenses). docs/sony-lens-corrections.md gains a pointer to it.
Tracker rows LR-EDIT-OPTICS-PROFILE (one note for both bodies) and
LR-IMP-CAMERA-COVERAGE in docs/parity-checklist.md, gap 8 in
docs/gaps.md, the lens-profile section of docs/raw-parity.md (lens score
unchanged), whats-new (lossless ARWs now; Compressed / Compressed HQ once
the ARW 6.0 decoder, #625, lands) and the colour-fit follow-up note are
updated.
Co-Authored-By: Claude <noreply@anthropic.com>
Keep image framing inside the validated 3:2 scope even when DefaultCrop retains native geometry. Cover all 23 Sony fixtures, preserve crop precedence, invalidate old renders, and record fresh Sony reference measurements.
Co-authored-by: Codex <noreply@openai.com>
Main (#575, #580) rewrote default_crop. The image crop now keeps main's
order for every Sony body (Sony's crop tags, then DefaultCrop, then the
recorded-size crop), so framing does not change. Only the ILCE-7RM4A
distortion warp takes its centre and normalization from DefaultCrop when
the file has one, which keeps the geometry validated against Sony's
exports (centre x 4783.5 on the A7R IVA sample). The DNG round-trip test
now checks both: Sony's crop on the image, the warp centred on the
default crop. RENDER_CACHE_VERSION 38.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Brandon Thomas