AVCaptureVideoDataOutput stops zooming while AVCaptureVideoPreviewLayer continues — physical wide / ultra-wide / telephoto only

Question

Created Apr ’26

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We use a single AVCaptureSession with AVCaptureVideoPreviewLayer and AVCaptureVideoDataOutput (preview-sized buffers, BGRA).

When we increase videoZoomFactor, beyond a certain zoom level the image from AVCaptureVideoDataOutput no longer zooms further, while AVCaptureVideoPreviewLayer continues to zoom with the same zoom control. The preview and the video-data output therefore diverge.

This behavior appears when the active camera is a physical lens device — wide, ultra-wide, or telephoto (e.g. builtInWideAngleCamera, builtInUltraWideCamera, builtInTelephotoCamera, or similar). It does not appear when the active input is a virtual / multi-camera (e.g. triple camera, dual-wide, or other system multi-camera).

Are there known conditions under which this mismatch between preview and video-data output is expected?

Thank you.

Answer 1

DTS Engineer OP

Apple

Apr ’26

Hello m131,

Thanks for raising this issue. I don't believe this discrepancy between AVCaptureVideoDataOutput and AVCaptureVideoPreviewLayer is expected. This may be worth filing a bug report to via Feedback Assistant. Once you open the bug report, please post the FB number here for my reference.

If you have any questions about filing a bug report, take a look at Bug Reporting: How and Why?

Thanks for reporting,

Richard Yeh  Developer Technical Support

Answer 2

testinstadev OP

3d

I have confirmed this is a bug that still exists on iOS 27. With 1920x1080 preset enabled along with second preview Video Data Output and stabilisation on main VDO set to anything other than .off, and preview VDO stabilisation set to .off, zoom stalls. Workaround is to use 4K preset instead, or set preview VDO stabilisation mode to .standard.