Composite of reduced but not cropped images using the 70-200 f/4L with Kenko Tubes. Only 3 of the 7 possible combinations of the three tubes are shown but the others would be intermediate values to those shown. In each set, the top row shows the result with the lens focus set to Infinity while the focus in the second row was set to the nearest setting (1.2m/4ft). Part of the surprises in these results probably relate to the internal focus system of the lens. As the tube extension relative to the focal length increases, the effect of the lens focus system decreases. With 68mm tubes and 70mm lens zoom setting, there is almost no change. The left column shows the close focus result of the lens used without any tubes. The 68mm tubes at 70mm zoom required removal of the lens hood since the subject was closer than the length of the hood.