Can only be used with full zoom
The E550 is a good camera and this lens does do a good job of zooming in on the subject but due to the way the camera and lens are designed, you must have the camera's zoom fully extended in order to use this tele lens. So this means if the subject is moving around a lot, such as my daughter playing soccer, you will miss the shots where the action has moved to close to you because you can't zoom out. As long as the action remains at some distance to you than this zoom lens is useful. I unfortunately have too many ruined shots because the action moved too close and their heads get cut off, etc.Another negative is that the viewfinder doesn't show the zoomed in image, you must use the lcd screen to frame a shot, which can be difficult in bright sunlight.