Photos & Camera

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Explore technical aspects of capturing high-quality photos and videos, including exposure control, focus modes, and RAW capture options.

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Format of 14-bit RAW bayer data from lower bit camera sensor?
I'm working on an application that uses the iPhone camera for scientific purposes - and, as a result would like to receive sensor data in as unprocessed format as possible. I'm using AVCapturePhotoOutput to take Bayer RAW stills and receiving data in kCVPixelFormatType_14Bayer_RGGB format. However, I'm puzzled as to the content of the bits. I simply demosaic the image by taking each 2x2 square: RG GB and use R, (G+G)/2, B to get 16-bit RGB values - and this indeed works. However, I am puzzled as to the values we are getting as they seem to be approximately in the range 2048 - 16383. The top value is understandable - the maximum that you can fit in 14-bits (as implied by the pixel format type). However we don't seem to be able to get lower than ~2048 no matter how black/dark we make the sensor. I'm aware that the sensor is probably not 14-bits (we're using the iPhone 16e camera) and that maybe this is to do with the way the sensor data is packaged. The Advances in iOS Photography video (https://developer.apple.com/videos/play/wwdc2016/501/) describes it as "10-bit sensor RAW packaged in 14 bits per pixel instead of eight." Is there any documentation describing what is going on here? It's vital for our use that we get as close to the raw camera sensor light readings as possible, so any pointers as to the mapping (e.g. decompanding?) being used would be extremely useful. Many thanks in advance for your help.
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May ’25
Significant Uptick in AVCaptureSessionWasInterrupted (Reason 4) Leading to Camera Black Screen and AVError Code -11803
In the latest production release of our iOS app (deployed via the App Store), we’ve observed a significant increase in AVCaptureSessionWasInterrupted notifications where the interruption reason has a rawValue of 4. The session does not automatically recover, even after returning from background or deleting/reinstalling the app. An employee ran into this and was able to get a recording. We see the below error when attempting to take photos. "Error Domain=AVFoundationErrorDomain Code=-11803 \"Cannot Record\" UserInfo={AVErrorRecordingFailureDomainKey=3, NSLocalizedDescription=Cannot Record, NSLocalizedRecoverySuggestion=Try recording again.}", } This interruption causes the camera preview to remain black, and any attempt to capture an image results in a failure with the following error: Some questions from our team: What common system conditions or foreground app behaviors can cause .videoDeviceNotAvailableWithMultipleForegroundApps (reason 4) to become persistent? Our teams under is under the impression the interruption reason 4 is mostly associated with iPad and PiP, but neither of these are true in the logs we see. Is manual recovery of the session required? Is there a recommended strategy to detect that the session is unrecoverable and gracefully notify the user or rebuild the session? Is there an instrument(s) in XCode you would recommend when trying to evaluate the increase in reason 4? Best, Ben
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603
Jun ’25
Telephoto Lens Keeps Switching to Other Lenses on iPhone 16 Pro Max During PPG (Finger on Camera)
Hi, I’m building a PPG-based heart rate feature where the user places their finger over the rear telephoto camera. On iPhone 16 Pro Max, I'm explicitly selecting the telephoto lens like this: videoDevice = AVCaptureDevice.default(.builtInTelephotoCamera, for: .video, position: .back) And trying to lock it: if #available(iOS 15.0, *), device.activePrimaryConstituentDeviceSwitchingBehavior != .unsupported { try? device.lockForConfiguration() device.setPrimaryConstituentDeviceSwitchingBehavior(.locked, restrictedSwitchingBehaviorConditions: []) device.unlockForConfiguration() } I also lock everything else to prevent dynamic changes: try device.lockForConfiguration() device.focusMode = .locked device.exposureMode = .locked device.whiteBalanceMode = .locked device.videoZoomFactor = 1.0 device.automaticallyEnablesLowLightBoostWhenAvailable = false device.automaticallyAdjustsVideoHDREnabled = false device.unlockForConfiguration() Despite this, the camera still switches to another lens, especially under different lighting, even though the user’s finger fully covers the lens. Questions: How can I completely prevent lens switching in this scenario? Would using videoZoomFactor = 3.0 or 5.0 better enforce use of the telephoto lens? Thanks! Gal
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185
Jul ’25
How to transcode HEIC to JPEG while preserving the ISO 21496-1 gain map
When shooting with an iPhone 15 or later, it’s possible to capture HEIC or JPEG images that include gain map information conforming to the ISO 21496-1 standard. However, during image format transcoding, the HEIC codec is able to preserve the ISO 21496-1 gain map. But when converting from HEIC to JPEG, the gain map is transformed into the Apple Gain Map format instead. Is there any solution to this issue?
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1.2k
Jul ’25
Why Does AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableWithMultipleForegroundApps Occur on iPhone?
Hi everyone, We're encountering an unexpected issue with our iPhone-only camera app: 👉 TimeMark - Photo Proof https://apps.apple.com/us/app/timemark-photo-proof/id6446071834 Problem Description: Our app uses a full-screen camera view via AVCaptureSession. In some cases reported by users, the camera fails immediately upon app launch, and we receive this interruption reason: AVCaptureSessionInterruptionReasonVideoDeviceNotAvailableWithMultipleForegroundApps According to the Apple documentation https://developer.apple.com/documentation/avfoundation/avcapturesession/interruptionreason/videodevicenotavailablewithmultipleforegroundapps?language=objc , this interruption typically occurs when the app is running in a multi-app layout such as Slide Over, Split View, or Picture in Picture — all of which are iPad-only features. However, this issue is being reported on iPhones, and our app does not support iPad at all. Also noted in the documentation: "Given your present AVCaptureSession configuration, the session may only be run if your app occupies the full screen." Additional Context: The issue occurs immediately on app launch, before the user can interact with the camera. We don’t enable multitaskingCameraAccessEnabled. We are 100% sure this is happening on iPhone, not iPad. It’s hard to reproduce; users report it happening sporadically. Locally, we tried playing Picture-in-Picture videos (e.g., Safari/YouTube) before launching our app, but we could not reproduce the issue. Questions: Why is this interruption reason occurring on iPhone, which doesn’t officially support Slide Over or Split View? Could this be caused by some system-level multitasking or resource contention (e.g., Picture in Picture from FaceTime or Safari)? Would enabling multitaskingCameraAccessEnabled help prevent this issue on iPhone, even though it's designed for iPad? Enabling multitaskingCameraAccessEnabled seems to require enabling UIBackgroundModes → voip. Would adding this background mode cause any App Store review risk or rejection if our app doesn't actually use VoIP functionality? Any help, insight, or suggestions would be greatly appreciated. Thanks in advance!
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866
Oct ’25
AVCaptureSession startRunning is slow
AVCaptureSession's startRunning method is thread blocking and seems to be slow. What is this method doing behind the scenes? For context: I'm working on Simulator Camera support and I have a 'fake' AVCaptureDevice that might be causing this. My hypothesis is that AVCaptureSession tries to connect to the device and waits for a notification to be posted back. I'd love to find a way to let my fake device message AVCaptureSession that it's connected.
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294
Jul ’25
Is Photo Library access mandatory for 24MP Deferred Photo Capture?
Hello everyone, I'm working on a feature where I need to capture the highest possible quality photo (e.g., 24MP on supported devices) and upload it to our server. I don't need the photos to appear in user's main Photos app so I thought I could store the photos in app's private directory using FileManager until they are uploaded. This wouldn't require requesting Photo Library permission, maximizing user privacy. The documentation on AVCapturePhotoOutput states that "the 24MP setting (5712, 4284) is only serviced as 24MP when opted-in to autoDeferredPhotoDeliveryEnabled" /** @property maxPhotoDimensions @abstract Indicates the maximum resolution of the requested photo. @discussion Set this property to enable requesting of images up to as large as the specified dimensions. Images returned by AVCapturePhotoOutput may be smaller than these dimensions but will never be larger. Once set, images can be requested with any valid maximum photo dimensions by setting AVCapturePhotoSettings.maxPhotoDimensions on a per photo basis. The dimensions set must match one of the dimensions returned by AVCaptureDeviceFormat.supportedMaxPhotoDimensions for the current active format. Changing this property may trigger a lengthy reconfiguration of the capture render pipeline so it is recommended that this is set before calling -[AVCaptureSession startRunning]. Note: When supported, the 24MP setting (5712, 4284) is only serviced as 24MP when opted-in to autoDeferredPhotoDeliveryEnabled. */ @available(iOS 16.0, *) open var maxPhotoDimensions: CMVideoDimensions (btw. this note is not present in the docs https://developer.apple.com/documentation/avfoundation/avcapturephotooutput/maxphotodimensions) Enabling autoDeferredPhotoDeliveryEnabled means that for a 24MP capture, the system will call the photoOutput(_:didFinishCapturingDeferredPhotoProxy:error:) delegate method, providing a proxy object instead of the final image data. According to the WWDC23 session "Create a more responsive camera experience," this AVCaptureDeferredPhotoProxy must be saved to the PHPhotoLibrary using a PHAssetCreationRequest with the resource type .photoProxy. The system then handles the final processing in the background within the library. To use deferred photo processing, you'll need to have write permission to the photo library to store the proxy photo, and read permission if your app needs to show the final photo or wants to modify it in any way. https://developer.apple.com/videos/play/wwdc2023/10105/?time=799 This seems to create a hard dependency on the Photo Library for accessing 24MP images. My question is: Is there any way to receive the final, processed 24MP image data directly in the app after a deferred capture, without using PHPhotoLibrary as the processing intermediary? For example, is there a delegate callback or a mechanism I'm missing that provides the final data for a deferred photo, allowing an app to handle it in-memory or in its own private sandbox, completely bypassing the user's Photo Library? Our goal is to follow Apple's privacy-first principles by avoiding requesting a PHPhotoLibrary authorization when our app's core function doesn't require access to the user's photo collection. Thank you for your time and any clarification you can provide.
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601
Sep ’25
Capturing 48mp photos with .builtInTripleCamera
I am able to capture 48mp photos using .builtInWideAngleCamera, but it seems like .builtInTripleCamera is capped at 12mp? Is there a way to capture 48mp photos using .builtInTripleCamera? Because .builtInTripleCamera provides smooth transition between cameras during zooming, and I'd like to keep this behavior. New iPhone 17 Pro have all their cameras at 48mp. Is there a chance that their .builtInTripleCamera is capable of capturing 48mp? Or is this an API limitation?
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439
Sep ’25
Launch The Main App from LockedCameraCapture
If the app is launched from LockedCameraCapture and if the settings button is tapped, I need to launch the main app. CameraViewController: func settingsButtonTapped() { #if isLockedCameraCaptureExtension //App is launched from Lock Screen //Launch main app here... #else //App is launched from Home Screen self.showSettings(animated: true) #endif } In this document: https://developer.apple.com/documentation/lockedcameracapture/creating-a-camera-experience-for-the-lock-screen Apple asks you to use: func launchApp(with session: LockedCameraCaptureSession, info: String) { Task { do { let activity = NSUserActivityTypeLockedCameraCapture activity.userInfo = [UserInfoKey: info] try await session.openApplication(for: activity) } catch { StatusManager.displayError("Unable to open app - \(error.localizedDescription)") } } } However, the documentation states that this should be placed within the extension code - LockedCameraCapture. If I do that, how can I call that all the way down from the main app's CameraViewController?
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569
Nov ’25
Photos are captured with incorrect exposure bias in specific scenarios on iPhone 17 Pro
Hey, There seems to be an inconsistency when capturing a photo using QualityPrioritization.Quality on the iPhone 17 Pro Main wide Lens. If you zoom above "2x" the output image always has "-2.0ev" bias in the meta data and looks underexposued. This does not happen at zoom levels above 2, or if you set the QualityPrioritization to .Balanced. See below: with .Quality with .Balanced This does not happen on the other lenses. I'm using a simple set up and it is consistent across JPEG and ProRAW capture. I have a demo project if that is useful. Thanks, Alex
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534
Dec ’25
CIRAWFilter.outputImage first-time cost is huge (~3s), subsequent calls are ~3ms. Any official way to pre-initialize RAW pipeline (without taking a real photo)?
Hi Apple Developer Forums, I’m developing an iOS camera app that processes RAW captures using Core Image. I’m seeing a large “first use” performance penalty specifically when creating the CIImage from CIRAWFilter.outputImage. What’s slow (important detail) I’m measuring the time for: let rawFilter = CIRAWFilter(imageData: rawData, identifierHint: hint) let ciImage = rawFilter.outputImage This is not CIContext.render(...) / createCGImage(...). It’s just the time to access outputImage (i.e., building the Core Image graph / RAW pipeline setup). Observed behavior First time accessing CIRAWFilter.outputImage: ~3 seconds Second time (same app session, similar RAW): ~3 milliseconds So something heavy is happening only on first use (decoder initialization, pipeline setup, shader/library compilation, caching, etc.). Using Metal System Trace, I also noticed that during the slow first call there are many “Create MTLLibrary” events, while the second call doesn’t show this pattern. Warm-up attempts using bundled DNG I tried to “warm up” early (e.g., on camera screen entry) by loading a bundled DNG and then accessing CIRAWFilter.outputImage by taking a photo: Warm-up with a ~247 KB DNG → first real RAW outputImage cost drops to ~1.42s Warm-up with a ~25 MB DNG → first real RAW outputImage cost drops to ~843ms This helps, but it’s still far from the steady-state ~3ms. Warm-up by capturing a real RAW (works, but concerns) The only method that fully eliminates the delay is to trigger a real RAW capture programmatically before the user’s first photo, then use that captured rawData to warm up the CIRAWFilter.outputImage path. This brings the first user-facing capture close to the steady-state timing. However: In some regions, the camera shutter sound cannot be suppressed, so “hidden warm-up capture” is unacceptable UX. I’m also unsure whether triggering a real capture without an explicit user action could raise compliance/privacy concerns, even if the image is immediately discarded and never saved/uploaded. Questions Is the large first-time cost of CIRAWFilter.outputImage expected (RAW pipeline initialization / shader compilation)? Is there an Apple-recommended way to pre-initialize the Core Image RAW pipeline / Metal resources so the first outputImage is fast, without taking a real photo? Are there any best practices (e.g. CIContext creation timing, prepareRender(...), specific options) that reliably reduce this first-use overhead for CIRAWFilter? Attachments Figure 1: First RAW capture with no warm-up (~3s outputImage time) Figure 2: First RAW capture after warm-up with bundled DNG (improved but still hundreds of ms) Thanks for any guidance or experience sharing!
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612
Jan ’26
dyld[434]: Library not loaded: error when running LockedCameraCapture compatible app on iOS 15
Hello, I am getting the following error while attempting to run my LockedCameraCapture compatible app on an iOS 15 device: dyld[434]: Library not loaded: '/System/Library/Frameworks/LockedCameraCapture.framework/LockedCameraCapture' Referenced from: '/private/var/containers/Bundle/Application/.../MyApp.app/MyApp.debug.dylib' Reason: tried: '/System/Library/Frameworks/LockedCameraCapture.framework/LockedCameraCapture' (no such file) Of course iOS 15 doesn't have the library for LockedCameraCapture, but I have had no issue including Lock Screen Widgets (which require iOS 16), so I am not sure why the error is popping up. Thank you!
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524
Mar ’25
Unable to Capture 24MP Photos
Hello, I'm wondering how to capture 24MP photos. I'm currently testing on an iPhone 16 Pro Max. By default, the device's activeFormat supports 24MP (photo dimensions: {4032x3024, 5712x4284}). For the photoOutput, I'm setting the maxPhotoDimensions to videoDevice.activeFormat.supportedMaxPhotoDimensions.lastObject, and setting MaxPhotoQualityPrioritization to quality. When capturing, I'm applying the same maxPhotoDimensions and photoQualityPrioritization settings from the photoOutput directly to the AVCapturePhotoSettings. What could be the issue? // Objective-C // setup [self.photoOutput setMaxPhotoQualityPrioritization:AVCapturePhotoQualityPrioritizationQuality]; CMVideoDimensions maxPhotoDimensions = [(NSValue *)videoDevice.activeFormat.supportedMaxPhotoDimensions.lastObject CMVideoDimensionsValue]; [self.photoOutput setMaxPhotoDimensions:maxPhotoDimensions]; // capturing AVCapturePhotoSettings *photoSettings = [AVCapturePhotoSettings photoSettings]; photoSettings.maxPhotoDimensions = self.photoOutput.maxPhotoDimensions; photoSettings.photoQualityPrioritization = self.photoOutput.maxPhotoQualityPrioritization; [self.photoOutput capturePhotoWithSettings:photoSettings delegate:photoCaptureDelegate]; ...
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978
Jan ’26
Torch Freezes Ultra-Wide Camera When Switching Between Wide & Ultra-Wide Lenses (AVFoundation Bug?)
I'm developing an iOS app using AVFoundation for real-time video capture and object detection. While implementing torch functionality with camera switching (between Wide and Ultra-Wide lenses), I encountered a critical issue where the camera freezes when toggling the torch while the Ultra-Wide camera is active. Issue If the torch is ON and I switch from Wide to Ultra-Wide, the camera freezes If the Ultra-Wide camera is active and I try to turn the torch ON, the camera freezes The iPhone Camera app allows using the torch while recording video with the Ultra-Wide lens, so this should be possible via AVFoundation as well. Code snippet DispatchQueue.global(qos: .userInitiated).async { [weak self] in guard let self = self else { return } let isSwitchingToUltraWide = !self.isUsingFisheyeCamera let cameraType: AVCaptureDevice.DeviceType = isSwitchingToUltraWide ? .builtInUltraWideCamera : .builtInWideAngleCamera let cameraName = isSwitchingToUltraWide ? "Ultra Wide" : "Wide" guard let selectedCamera = AVCaptureDevice.default(cameraType, for: .video, position: .back) else { DispatchQueue.main.async { self.showAlert(title: "Camera Error", message: "\(cameraName) camera is not available on this device.") } return } do { let currentInput = self.videoCapture.captureSession.inputs.first as? AVCaptureDeviceInput self.videoCapture.captureSession.beginConfiguration() if isSwitchingToUltraWide && self.isFlashlightOn { self.forceEnableTorchThroughWide() } if let currentInput = currentInput { self.videoCapture.captureSession.removeInput(currentInput) } let videoInput = try AVCaptureDeviceInput(device: selectedCamera) self.videoCapture.captureSession.addInput(videoInput) self.videoCapture.captureSession.commitConfiguration() self.videoCapture.updateVideoOrientation() DispatchQueue.main.async { if let barButton = sender as? UIBarButtonItem { barButton.title = isSwitchingToUltraWide ? "Wide" : "Ultra Wide" barButton.tintColor = isSwitchingToUltraWide ? UIColor.systemGreen : UIColor.white } print("Switched to \(cameraName) camera.") } self.isUsingFisheyeCamera.toggle() } catch { DispatchQueue.main.async { self.showAlert(title: "Camera Error", message: "Failed to switch to \(cameraName) camera: \(error.localizedDescription)") } } } } Expected Behavior Torch should be able to work when Ultra-Wide is active, just like the iPhone Camera app does. The camera should not freeze when switching between Wide and Ultra-Wide with the torch ON. AVCaptureSession should not crash when toggling the torch while Ultra-Wide is active. Questions & Help Needed Is this a known issue with AVFoundation? How does the iPhone Camera app allow using the torch while recording in Ultra-Wide? What’s the correct way to switch between Wide and Ultra-Wide cameras without freezing when the torch is active? Info Device tested: iPhone 13 Pro / iPhone 15 Pro / Iphone 15 iOS Version: iOS 17.3 / iOS 18.0 Xcode Version: 16.2
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705
Oct ’25
Crash in Photos framework
Hi This is one of our top crashes. It does not contain any of our code in the stacktrace and we can't reproduce it. Those points make this crash very hard to understand and fix. We know that most of the crashes are happening on iPhone 13 with iOS 18.x.x. Also we see that a lot of cases happen when app goes into background (stacktrace contains -[UIApplication _applicationDidEnterBackground]). 2025-03-04_16-06-00.3670_-0500-6a273c7d5da97f098b5cc24898bb9761dc45208e.crash 2025-03-04_20-21-08.6609_-0500-2c08f640900f8a62c4f8a4f6f2a61feb052e66dd.crash 2025-03-04_20-46-27.7138_+0000-4d7ea89b1b564eda22ca63e708f7ad3909c7b768.crash
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536
Mar ’25
Unable to Fetch Videos from Recently Deleted Album Using Photos Framework in iOS 18.3.1
Hello everyone, I’m working on an iOS app that fetches videos from the "Recently Deleted" album using the Photos framework in Swift. However, I’m unable to fetch any videos, even though the "Recently Deleted" album contains 233 items (including videos), as seen in the Photos app. Environment: iOS Version: 18.3.1 Xcode Version: 16.2 Swift Version: Swift 5 Device: iPhone (simulator and physical device both tested) Photo Library Permission: "All Photos" access granted Recently Deleted Lock: Face ID/Passcode is disabled for "Recently Deleted"
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154
Mar ’25
Images with unusual color spaces not correctly loaded by Core Image
Some users reported that their images are not loading correctly in our app. After a lot of debugging we identified the following: This only happens when the app is build for Mac Catalyst. Not on iOS, iPadOS, or “real” macOS (AppKit). The images in question have unusual color spaces. We observed the issue for uRGB and eciRGB v2. Those images are rendered correctly in Photos and Preview on all platforms. When displaying the image inside of a UIImageView or in a SwiftUI Image, they render correctly. The issue only occurs when loading the image via Core Image. When comparing the different Core Image render graphs between AppKit (working) and Catalyst (faulty) builds, they look identical—except for the result. Mac (AppKit): Catalyst: Something seems to be off when Core Image tries to load an image with foreign color space in Catalyst. We identified a workaround: By using a CGImageDestination to transcode the image using the kCGImageDestinationOptimizeColorForSharing option, Image I/O will convert the image to sRGB (or similar) and Core Image is able to load the image correctly. However, one potentially loses fidelity this way. Or might there be a better workaround?
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Aug ’25