Anamorphic de-squeeze for still-photo preview

[erik-sutton95]

Goal

Add non-destructive anamorphic de-squeeze to still-photo preview and playback so photographers using anamorphic lenses can judge composition and focus without viewing the captured image in its squeezed form.

Why it matters

OpenZCine already treats de-squeeze as an important cinema monitoring tool, but anamorphic lenses are also used for still photography. A squeezed photo preview makes faces, framing, and edge behavior difficult to evaluate during a tethered shoot.

Proposed experience

• Offer the same supported de-squeeze ratios used by live view and video playback, including the current presets and custom ratio where available.
• Apply de-squeeze to JPEG, HEIF, and decodable RAW previews, including embedded previews when the full RAW cannot be rendered directly.
• Keep the original photo untouched; this is a display transform only.
• Provide Fit, zoom, and pan after de-squeeze, with an obvious reset.
• Retain focus inspection at useful magnifications without introducing avoidable interpolation softness.
• Allow the selected ratio to follow the current monitoring session or a saved anamorphic-lens preset.
• Clearly indicate when de-squeeze is active so the user does not mistake the preview geometry for a baked crop.
• Use the same geometry model on iOS, iPadOS, and Android.

Interaction with framing

• Allow post-de-squeeze aspect-ratio guides over the photo preview.
• When Guide Fill is implemented, allow the selected guide to fill the photo viewer without altering the source file.
• Keep export/share unchanged unless a separate explicit transformed-copy export is added later.

Success looks like

After capturing a still with an anamorphic lens, the operator opens the photo preview, selects the correct de-squeeze ratio, and can judge the image at the intended geometry and inspect focus without changing the camera original.

Open questions

• Which still formats and embedded RAW previews are available consistently from each supported Nikon body?
• Should the app infer the ratio from the active live-view setting, remember it per lens preset, or require explicit selection?
• Can full-resolution focus inspection stay responsive while de-squeezing large stills?
• Should sidecar metadata record the chosen viewing ratio without modifying the image?

Related OpenZCine work

• Live tethering and photography mode
• Playback de-squeeze
• Post-de-squeeze crop-to-guide Fit/Fill monitoring

[erik-sutton95]

Additional Reddit demand explicitly asks for de-squeeze ratios—including an ideal custom ratio—while photographing with anamorphic lenses. This supports carrying the same preset/custom-ratio model into still preview instead of limiting the first version to a single fixed squeeze.

Reddit source

[erik-sutton95]

Implemented on feat/playback-fullscreen-and-photo-desqueeze (f775df3), both platforms, across every photo-mode surface: live view, instant playback, and the media-page still viewer.

The core of it was one flag — appliesToPhotography returned false for de-squeeze, and both shells route the photography filter through it, so flipping it fixes live view outright.

The stills surfaces needed a different transform, and the reason is worth recording: a still is fitted to its container first, so scaling after the fit pushes the image outside the frame it was just fitted into — and on instant review it drags the AF box with it, since those boxes derive their scale from the fitted rect. So de-squeeze changes the fit, not the scale. Everything anchored to the resulting box (AF overlay, pinch zoom, focus inspection) then follows for free.

Per your Reddit note, all presets and the custom 1.00–2.00× factor come along — it is the same Desqueeze model the cinema path already reads, so nothing here is a fixed single ratio. Display transform only: camera original and export unchanged.

Not yet seen with an actual anamorphic still — no squeezed test image here, so that is the first thing to check on hardware.

[erik-sutton95]

This has shipped — anamorphic de-squeeze now applies in photo mode, including live view and instant playback, alongside the video path. Thanks for the request.