diff --git a/src/ol/renderer/canvas/canvasmaprenderer.js b/src/ol/renderer/canvas/canvasmaprenderer.js
index 4780c811f1..86d1afbfcf 100644
--- a/src/ol/renderer/canvas/canvasmaprenderer.js
+++ b/src/ol/renderer/canvas/canvasmaprenderer.js
@@ -120,8 +120,8 @@ ol.renderer.canvas.Map.prototype.renderFrame = function(frameState) {
 
   var layerStates = frameState.layerStates;
   var layersArray = frameState.layersArray;
-  var i, image, layer, layerRenderer, layerState, transform;
-  for (i = 0; i < layersArray.length; ++i) {
+  var i, ii, image, layer, layerRenderer, layerState, transform;
+  for (i = 0, ii = layersArray.length; i < ii; ++i) {
 
     layer = layersArray[i];
     layerRenderer = this.getLayerRenderer(layer);
diff --git a/src/ol/renderer/canvas/canvastilelayerrenderer.js b/src/ol/renderer/canvas/canvastilelayerrenderer.js
index 55ffae16b7..3bb0fef9d1 100644
--- a/src/ol/renderer/canvas/canvastilelayerrenderer.js
+++ b/src/ol/renderer/canvas/canvastilelayerrenderer.js
@@ -303,8 +303,8 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
     }
   }
 
-  var i;
-  for (i = 0; i < tilesToClear.length; ++i) {
+  var i, ii;
+  for (i = 0, ii = tilesToClear.length; i < ii; ++i) {
     tile = tilesToClear[i];
     x = tileSize.width * (tile.tileCoord.x - canvasTileRange.minX);
     y = tileSize.height * (canvasTileRange.maxY - tile.tileCoord.y);
@@ -321,7 +321,7 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
   var currentZ, index, scale, tileCoordKey, tileExtent, tilesToDraw;
   var ix, iy, interimTileExtent, interimTileRange, maxX, maxY;
   var height, width;
-  for (i = 0; i < zs.length; ++i) {
+  for (i = 0, ii = zs.length; i < ii; ++i) {
     currentZ = zs[i];
     tileSize = tileGrid.getTileSize(currentZ);
     tilesToDraw = tilesToDrawByZ[currentZ];