Merge PR #1423

docs/merge.md

@@ -27,6 +27,11 @@ homography (the simplest model that explains ≥ 97 % of the matches). Exposure
 Radiance is a weighted mean in linear light, weight `k · (1 − smoothstep(0.8·clip, 0.96·clip, max
 channel))`. Deghost: a per-pixel consistency test against the reference radiance (with a noise
 floor), dilated and feathered masks; the union is the deghost overlay. Output: 16-bit float DNG.
+Lens corrections: frames are merged uncorrected, and the DNG's `OpcodeList3` carries the reference frame's
+(`WarpRectilinear`, `WarpRectilinear2`, `FixVignetteRadial`: a DNG's own, or a camera's correction a raw reader
+converts, e.g. Sony, Panasonic), re-expressed for its default crop (`Opcode::cropped`). So Optics ▸ Enable Lens
+Corrections works on the result as on the sources; a vertical bracket keeps its pixels unturned and its
+corrections.
 
 **Panorama** (`pano/`): MOPS-style features, pairwise RANSAC homographies with Brown & Lowe's
 verification, focal from homographies (or EXIF 35 mm), rotations chained along a maximum spanning
@@ -54,7 +59,9 @@ scale in `BaselineExposure`; raw sources keep their DNG colour tags (camera RGB)
 ## Limits (known gaps)
 
 - No lens-distortion model in the panorama bundle adjustment (rectilinear lenses assumed); no
-  360° wrap-around; flat (translating-camera) scans are fitted with the rotation model.
+  360° wrap-around; flat (translating-camera) scans are fitted with the rotation model. Panoramas and HDR
+  panoramas carry no lens corrections, nor does an HDR whose frames don't share an orientation (they are turned
+  before merging).
 - No camera response calibration for JPEG brackets (sRGB decoding is taken as linear light).
 - Boundary Warp is a separable stretch, not a content-preserving mesh warp; Fill Edges is diffusion,
   not patch synthesis.

docs/parity-checklist.md

@@ -347,7 +347,7 @@ differences and missing bindings are in [ui-parity.md](ui-parity.md#shortcuts).
 
 | Id | Feature | Tier | Status | Evidence | Missing / notes |
 |---|---|---|---|---|---|
-| LR-MERGE-HDR | HDR merge | P2 | ✅ | `cmd:merge.hdr`, `cmd:dialog.mergeHdr` | auto align, deghost None–High + overlay, auto settings, float DNG, Create Stack; JPEG brackets treated as linear; raws without colour matrices of their own (CR2, NEF, ARW…) keep the colour they open with, written as DNG tags (`starting_colour_tags`; the look's chroma curve has no tag; panoramas too), issue #965 |
+| LR-MERGE-HDR | HDR merge | P2 | ✅ | `cmd:merge.hdr`, `cmd:dialog.mergeHdr`, `crates/merge/src/frame.rs` (`Frame::lens`) | auto align, deghost None–High + overlay, auto settings, float DNG, Create Stack; the DNG keeps the reference frame's embedded lens corrections (tested by `hdr_merge_keeps_the_reference_frames_lens_corrections`); JPEG brackets treated as linear; raws without colour matrices of their own (CR2, NEF, ARW…) keep the colour they open with, written as DNG tags (`starting_colour_tags`; the look's chroma curve has no tag; panoramas too), issue #965 |
 | LR-MERGE-PANO | Panorama | P2 | ✅ | `cmd:merge.panorama`, `cmd:dialog.mergePanorama` | spherical/cylindrical/perspective + auto, boundary warp, auto crop, fill edges (diffusion), DNG; no lens model / 360° wrap |
 | LR-MERGE-HDRPANO | HDR panorama | P2 | ✅ | `cmd:merge.hdrPanorama`, `cmd:dialog.mergeHdrPanorama` | brackets grouped by EXIF |
 | LR-MERGE-HEADLESS | Merge with last settings | P2 | ✅ | `cmd:merge.hdrLast`, `cmd:merge.panoramaLast`, `cmd:merge.hdrPanoramaLast` | no dialog; the options of the last merge of that kind (defaults the first time) |

docs/whats-new.md

@@ -2,6 +2,11 @@
 
 ## 2026-10-13
 
+### HDR merges keep the lens correction
+- An HDR made with Photo ▸ Photo Merge ▸ HDR now keeps the lens correction the photos carry (Sony's, Panasonic's
+  and Leica's, and the one some DNGs carry, e.g. from drones): Optics ▸ Enable Lens Corrections straightens it as it
+  does the photos it was made from. HDRs merged before this don't have it; merge them again.
+
 ### Slider drags on large raws
 - Dragging a slider no longer re-renders the edited photo's filmstrip thumbnail on every frame; it follows once you
   let go. On a 64 MP raw the first of those renders decoded the whole file again, which held up the loupe's