iOS 7 Lossless Video Zooming Report from Imaging & Video Guru
By Werner Ruotsalainen
This article is highly recommended for programmers and people interested in shooting video.
As of iOS 7 beta 2, the built-in Camera application can't make use of the extra pixels of the sensor when zooming. Only custom-written, third-party apps currently can do that. Hopefully Apple fixes Camera in the final version of iOS 7; before that, should you want to use zooming while shooting video, avoid using the Camera app and make sure you write or install an iOS 7-specific video recorder application for best results.
Many of my readers have asked for a complete elaboration on the brand new zooming features of iOS 7, both in the stock Camera application and the programmatic API support (AVCaptureDevice.videoZoomFactor and the related, highly useful properties AVCaptureDevice.activeFormat.videoZoomFactorUpscaleThreshold and AVCaptureDevice.activeFormat.videoMaxZoomFactor).