or even better;
_tf.filters = [filter(4,153,0xffffff,0.7,4,4,0.7,0.15,false,false,false)]; function filter(distance, angle, color, alpha, blurX, blurY, strength, quality, inner, knockout, hideObject){ return new DropShadowFilter(distance, angle, color, alpha, blurX, blurY, strength, quality, inner, knockout, hideObject); }
another way:
_tf.filters = [new DropShadowFilter(4.0,45,0x000000,1.0,4.0,4.0,1.0,1,false,true,false)]; /* DropShadowFilter(distance:Number = 4.0, angle:Number = 45, color:uint = 0, alpha:Number = 1.0, blurX:Number = 4.0, blurY:Number = 4.0, strength:Number = 1.0, quality:int = 1, inner:Boolean = false, knockout:Boolean = false, hideObject:Boolean = false); DropShadowFilter distance:Number = 4.0 angle:Number = 45 color:uint = 0 alpha:Number = 1.0 blurX:Number = 4.0 blurY:Number = 4.0 strength:Number = 1.0 quality:int = 1 inner:Boolean = false knockout:Boolean = false hideObject:Boolean = false */
here: http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/filters/DropShadowFilter.html