 Also, it can be compared to the three Canon EF 24–70 mm L lenses.Two of the 24–70 lenses have the same 2.8 maximum aperture as the 17–55, but no image stabilization; the newest 24–70 has a maximum 4 aperture but adds stabilization.When mounted on their equivalent cameras (full-frame for the 24–70, and crop for the 17–55), the two lenses have similar focal lengths.