diff --git a/src/iiiftilesource.js b/src/iiiftilesource.js
index ae1896df..908fc38d 100644
--- a/src/iiiftilesource.js
+++ b/src/iiiftilesource.js
@@ -65,9 +65,18 @@ $.IIIFTileSource = function( options ){
     //      to preserve backward compatibility.
     options.tileSize = this.tile_width;
 
-    options.maxLevel = options.maxLevel ? options.maxLevel : Number(
-        Math.ceil( Math.log( Math.max( this.width, this.height ), 2 ) )
-    );
+    if (! options.maxLevel ) {
+        var mf = -1;
+        var scfs = this.scale_factors || this.scale_factor;
+        if ( scfs instanceof Array ) {
+            for ( var i = 0; i < scfs.length; i++ ) {
+                var cf = Number( scfs[i] );
+                if ( !isNaN( cf ) && cf > mf ) { mf = cf; }
+            }
+        }
+        if ( mf < 0 ) { options.maxLevel = Number(Math.ceil(Math.log(Math.max(this.width, this.height), 2))); }
+        else { options.maxLevel = mf; }
+    }
 
     $.TileSource.apply( this, [ options ] );
 };
@@ -176,7 +185,7 @@ $.extend( $.IIIFTileSource.prototype, $.TileSource.prototype, {
             iiif_tile_h;
 
 
-        if ( level_width < this.tile_width || level_height < this.tile_height ){
+        if ( level_width < this.tile_width && level_height < this.tile_height ){
             iiif_region = 'full';
         } else {
             iiif_tile_x = x * iiif_tile_size_width;