Continuous Zoom with tiled basemap
Is there a way to implement 'Continuous Zoom' the ArcGIS Online map viewer while using the default basemaps?
For the data on my map I need to be able to view it at about half way between two zoom levels, the steps between the levels are too large. I noticed in Google Maps zooming using the mouse wheel increments the zoom level by 0.25, this feels about right.
Doing this in ArcGIS Desktop is simple with the Continious Zoom tool or by holding 'B'.
The only way I've found of doing this on ArcGIS Online is by using a MapService as a basemap then zoom by holding the Shift key.
Why do ArcGIS Online maps require a basemap at all? What if I don't want one? Is there an empty/blank MapService I can use to work around this?
After adding a MapService as a basemap it allows continuous zoom to work, even after I replace it with a normal tiled basemap. However the continuous zoom stops working after refreshing the page 
