ios – AVCaptureDevice.exposurePointOfInterest readback does not match set value on iPad Pro M4 / M3(UltraWide)and Gen2,3,4(TrueDepth) using resizeAspectFill

Environment:

• Devices: iPad Pro 11″ M4, iPad Air 11″ M3, iPad Pro 11″ Gen2/3/4

• Language: Swift

• Framework: AVFoundation

• Front camera: UltraWide (M4/M3), TrueDepth (Gen2–4)

• Video gravity: .resizeAspectFill

Background

I am setting an exposure point of interest using coordinates defined in captured image pixel space.

• Input point: (1170, 1370)

Image sizes:

• Gen2/3/4: 2316 × 3088

• M3/M4: 3024 × 4032

Preview sizes:

• Gen2/3/4: 834 × 1194

• M4: 834 × 1210

• M3: 820 × 1180

What I do

First, I convert image pixel coordinates to preview layer coordinates, then use captureDevicePointConverted(fromLayerPoint:).

let devicePoint = previewLayer.captureDevicePointConverted(fromLayerPoint: layerPoint)

Reading back exposure point

After capture, I convert back:

let layerPoint = previewLayer.layerPointConverted(fromCaptureDevicePoint: exposurePoint)

This results in:

Observation

It seems that captureDevicePointConverted(fromLayerPoint:) does not perform a linear mapping when using .resizeAspectFill.

My understanding is that:

Questions

1. Does captureDevicePointConverted(fromLayerPoint:) account for .resizeAspectFill cropping, making it unsuitable for direct pixel mapping?

2. Is it correct to compute exposure points directly using normalized coordinates (pixel / image size) instead of using preview layer conversion?

3. Is exposurePointOfInterest always expressed in full sensor normalized coordinates (0–1), independent of preview settings?

4. Does this behavior differ between UltraWide (M3/M4) and TrueDepth cameras?

5. Is there official documentation describing correct coordinate mapping for this scenario?