fix: Restore CameraDevice neutralZoom

apps/simple-camera/__tests__/visioncamera.devices.harness.ts

@@ -94,6 +94,8 @@ describe('VisionCamera - Devices', () => {
   it('reports sane capability invariants for each device', () => {
     for (const device of factory.cameraDevices) {
       expect(device.minZoom).toBeLessThanOrEqual(device.maxZoom)
+      expect(device.neutralZoom).toBeGreaterThanOrEqual(device.minZoom)
+      expect(device.neutralZoom).toBeLessThanOrEqual(device.maxZoom)
 
       if (device.supportsExposureBias) {
         expect(device.minExposureBias).toBeLessThanOrEqual(

docs/content/docs/zooming.mdx

@@ -13,7 +13,7 @@ The [`<Camera />`](/api/react-native-vision-camera/views/Camera) view allows adj
 ```tsx
 function App() {
   // [!code ++]
-  const zoom = useSharedValue(device.minZoom)
+  const zoom = useSharedValue(device.neutralZoom)
 
   return (
     <Camera
@@ -48,7 +48,7 @@ To zoom on a [`CameraController`](/api/react-native-vision-camera/hybrid-objects
 const device = ...
 const controller = ...
 // [!code ++]
-await controller.setZoom(device.minZoom)
+await controller.setZoom(device.neutralZoom)
 ```
 </Tab>
 </Tabs>
@@ -97,12 +97,15 @@ for (const switchOverFactor of device.zoomLensSwitchFactors) {
 
 #### Default Zoom
 
-To provide a natural user experience, always start at zoom `1`.
-If a virtual Camera contains an [`'ultra-wide-angle'`](/api/react-native-vision-camera/type-aliases/DeviceType) Camera (the "0.5x Camera"), the user may zoom out to less than `1` (here `0.5`) instead.
+To provide a natural user experience, start at the Camera's [`neutralZoom`](/api/react-native-vision-camera/hybrid-objects/CameraDevice#neutralzoom).
+This is the internal zoom factor that appears as `1x` to the user and selects the standard wide-angle lens.
 
-- [`minZoom`](/api/react-native-vision-camera/hybrid-objects/CameraDevice#minzoom) &lt;= `1` (e.g. 0.5x)
-- natural zoom = `1`
-- [`maxZoom`](/api/react-native-vision-camera/hybrid-objects/CameraDevice#maxzoom) &gt;= `1` (e.g. 3x)
+On most Cameras `neutralZoom` is `1`, but iOS virtual Cameras that contain an [`'ultra-wide-angle'`](/api/react-native-vision-camera/type-aliases/DeviceType) lens can use a larger internal factor, such as `2`.
+In that case the user can still zoom out below `neutralZoom` to reach the ultra-wide-angle lens.
+
+- [`minZoom`](/api/react-native-vision-camera/hybrid-objects/CameraDevice#minzoom) &lt;= [`neutralZoom`](/api/react-native-vision-camera/hybrid-objects/CameraDevice#neutralzoom)
+- natural zoom = [`neutralZoom`](/api/react-native-vision-camera/hybrid-objects/CameraDevice#neutralzoom) (displayed as `1x`)
+- [`maxZoom`](/api/react-native-vision-camera/hybrid-objects/CameraDevice#maxzoom) &gt;= [`neutralZoom`](/api/react-native-vision-camera/hybrid-objects/CameraDevice#neutralzoom)
 
 ### Getting current zoom values
 

packages/react-native-vision-camera/android/src/main/java/com/margelo/nitro/camera/hybrids/inputs/HybridCameraDevice.kt

@@ -194,6 +194,7 @@ class HybridCameraDevice(
       val zoomState = cameraInfo.zoomState.value ?: return 0.0
       return zoomState.maxZoomRatio.toDouble()
     }
+  override val neutralZoom: Double = 1.0
   override val zoomLensSwitchFactors: DoubleArray
     get() = cameraInfo.zoomLensSwitchFactors
 

packages/react-native-vision-camera/android/src/main/java/com/margelo/nitro/camera/hybrids/inputs/HybridPhysicalCameraDevice.kt

@@ -92,6 +92,7 @@ class HybridPhysicalCameraDevice(
   override val supportsLowLightBoost: Boolean = false
   override val minZoom: Double = 0.0
   override val maxZoom: Double = 0.0
+  override val neutralZoom: Double = 1.0
   override val zoomLensSwitchFactors: DoubleArray = doubleArrayOf()
   override val supportsDistortionCorrection: Boolean = false
 

packages/react-native-vision-camera/ios/Extensions/AVFoundation/AVCaptureDevice+neutralZoom.swift

@@ -0,0 +1,40 @@
+///
+/// AVCaptureDevice+neutralZoom.swift
+/// VisionCamera
+/// Copyright © 2026 Marc Rousavy @ Margelo
+///
+
+import AVFoundation
+import Foundation
+
+extension AVCaptureDevice {
+  /**
+   * The internal video zoom factor that AVFoundation displays as `1x`.
+   *
+   * On older iOS versions, derive it from the switchover factor immediately
+   * before the standard wide-angle constituent Camera.
+   */
+  var neutralZoomFactor: Double {
+    if #available(iOS 18.0, *) {
+      let multiplier = displayVideoZoomFactorMultiplier
+      if multiplier > 0 {
+        return 1 / multiplier
+      }
+    }
+
+    guard
+      let wideAngleIndex = constituentDevices.firstIndex(where: {
+        $0.deviceType == .builtInWideAngleCamera
+      }),
+      wideAngleIndex > 0
+    else {
+      return 1
+    }
+
+    let switchoverIndex = wideAngleIndex - 1
+    guard virtualDeviceSwitchOverVideoZoomFactors.indices.contains(switchoverIndex) else {
+      return 1
+    }
+    return virtualDeviceSwitchOverVideoZoomFactors[switchoverIndex].doubleValue
+  }
+}

packages/react-native-vision-camera/ios/Hybrid Objects/Inputs/HybridCameraDevice.swift

@@ -221,6 +221,10 @@ final class HybridCameraDevice: HybridCameraDeviceSpec, NativeCameraDevice {
     return device.maxAvailableVideoZoomFactor
   }
 
+  var neutralZoom: Double {
+    return device.neutralZoomFactor
+  }
+
   var zoomLensSwitchFactors: [Double] {
     return device.virtualDeviceSwitchOverVideoZoomFactors.map { $0.doubleValue }
   }

packages/react-native-vision-camera/src/specs/inputs/CameraDevice.nitro.ts

@@ -578,6 +578,19 @@ export interface CameraDevice
    * for a true current maximum.
    */
   readonly maxZoom: number
+  /**
+   * The zoom factor at which this Camera appears naturally zoomed (`1x`)
+   * to the user.
+   *
+   * For physical Cameras and Android devices this is typically `1.0`.
+   * On iOS virtual Cameras that include an ultra-wide-angle lens, this can
+   * be greater than `1.0` because AVFoundation's internal zoom scale starts
+   * at the widest constituent lens.
+   *
+   * Use this value as the initial zoom if the Camera should start on its
+   * standard wide-angle lens while still allowing the user to zoom out.
+   */
+  readonly neutralZoom: number
   /**
    * If this {@linkcode CameraDevice} is a virtual device,
    * this returns a list of zoom factors at which the virtual