I have finally decided to purchase the cheapest telephoto lens, the Canon 50mm F1.8. Do not under estimate the price of this lens, the possibility hidden in this lens is huge. Not only it has a wide aperture and able to shoot in low light condition, but this lens is a creative lens. Because the aperture was built with only 5 blades, it allows me to change the shape of my bokeh (the round circle behind the picture). Fun! Another lens added in my collection.