public void SetCamera( 
   Bookmark bookmark
)

//Set the extent of a map frame to a bookmark.

//Perform on the worker thread
await QueuedTask.Run(() =>
{
  //Reference MapFrame
  MapFrame mf_bk = layout.FindElement("Map Frame") as MapFrame;

  //Reference a bookmark that belongs to a map associated with the map frame
  Map m = mf_bk.Map;
  Bookmark bk = m.GetBookmarks().FirstOrDefault(item => item.Name.Equals("Lakes"));

  //Set the map frame extent using the bookmark
  mf_bk.SetCamera(bk);
});

//Create a map frame and set its camera by zooming to the extent of an existing bookmark.

//Construct on the worker thread
await QueuedTask.Run(() =>
{
  //Build 2D envelope geometry
  Coordinate2D mf_ll = new Coordinate2D(6.0, 8.5);
  Coordinate2D mf_ur = new Coordinate2D(8.0, 10.5);
  //At 2.x - Envelope mf_env = EnvelopeBuilder.CreateEnvelope(mf_ll, mf_ur);
  Envelope mf_env = EnvelopeBuilderEx.CreateEnvelope(mf_ll, mf_ur);

  //Reference map, create MF and add to layout
  MapProjectItem mapPrjItem = Project.Current.GetItems<MapProjectItem>()
                       .FirstOrDefault(item => item.Name.Equals("Map"));
  Map mfMap = mapPrjItem.GetMap();
  Bookmark bookmark = mfMap.GetBookmarks().FirstOrDefault(
                        b => b.Name == "Great Lakes");

  //At 2.x - MapFrame mfElm =
  //                  LayoutElementFactory.Instance.CreateMapFrame(
  //                                             layout, mf_env, mfMap);
  //         mfElm.SetName("New Map Frame");
  //
  MapFrame mfElm = ElementFactory.Instance.CreateMapFrameElement(
                       layout, mf_env, mfMap, "New Map Frame");

  //Zoom to bookmark
  mfElm.SetCamera(bookmark);
});

//Change map frame extent to single feature with 10 percent buffer

//Process on the worker thread
await QueuedTask.Run(() =>
{
  //Reference the mapframe and its associated map
  MapFrame mf = layout.FindElement("Map Frame") as MapFrame;
  Map m = mf.Map;

  //Reference a feature layer and build a query (to return a single feature)
  FeatureLayer fl = m.FindLayers("GreatLakes").First() as FeatureLayer;
  QueryFilter qf = new QueryFilter();
  string whereClause = "NAME = 'Lake Erie'";
  qf.WhereClause = whereClause;

  //Zoom to the feature
  using (ArcGIS.Core.Data.RowCursor rowCursor = fl.Search(qf))
  {
    while (rowCursor.MoveNext())
    {
      //Get the shape from the row and set extent
      using (var feature = rowCursor.Current as ArcGIS.Core.Data.Feature)
      {
        Polygon polygon = feature.GetShape() as Polygon;
        Envelope env = polygon.Extent as Envelope;
        mf.SetCamera(env);

        //Zoom out 15 percent
        Camera cam = mf.Camera;
        cam.Scale = cam.Scale * 1.15;
        mf.SetCamera(cam);
      }
    }
  }
});