Hello, I have an iOS camera app that captures exposure brackets and performs custom HDR processing. On iOS 26, I’m observing a visual difference between: a single photo captured at –2 EV, and the –2 EV frame from an exposure bracket (–2 / 0 / +2 EV).
On iOS 26: The single –2 EV image looks natural and consistent. The –2 EV image from the bracket appears clamped / distorted, most noticeably in high dynamic range scenes (highlight compression and loss of detail). On iOS 18, both approaches produce visually identical and correct –2 EV images. The issue only appears for bracketed captures on iOS 26. Attachments (examples)
iOS 26 Single capture –2 EV (JPEG): /Users/danilobudimir/Downloads/ios26SingleImage/JPEG image-4006-8B77-51-0.jpeg
Single capture –2 EV — Capture report (dumped settings): /Users/danilobudimir/Downloads/ios26SingleImage/UnderExposureDebug_CaptureReport_2026-01-09T15-59-20Z.md
Bracket capture –2 EV frame (JPEG): /Users/danilobudimir/Downloads/bracket_iOS26/JPEG image-45CE-9793-A5-0.jpeg
Bracket capture — Capture report (dumped settings): /Users/danilobudimir/Downloads/bracket_iOS26/UnderExposureDebug_CaptureReport_2026-01-09T15-55-42Z.md
iOS 18 Single capture –2 EV (JPEG): /Users/danilobudimir/Downloads/ios18SingleImage/JPEG image-47FD-AF73-28-0.jpeg
Single capture –2 EV — Capture report: /Users/danilobudimir/Downloads/ios18SingleImage/UnderExposureDebug_CaptureReport_2026-01-09T16-25-27Z.md
Bracket capture — –2 EV frame (JPEG): /Users/danilobudimir/Downloads/bracket_iOS18/JPEG image-4A4C-9E93-46-0.jpeg
Bracket capture — Capture report: /Users/danilobudimir/Downloads/bracket_iOS18/UnderExposureDebug_CaptureReport_2026-01-09T16-27-23Z.md
Question Is there any new behavior in iOS 26 AVFoundation related to: AVCapturePhotoBracketSettings, tone mapping / HDR preprocessing, or internal image processing applied specifically to bracketed frames? Is there a new flag, format requirement or opt-out mechanism required to preserve linear underexposed frames in exposure brackets?