As Scotty would say, “You can’t change the laws of physics!”. But…you can cheat a little. All of our Tamron E-Mount lenses have a zoom range that is about 10% smaller than what would be considered “the norm” among other manufacturers. That small compromise pays big dividends when it comes to lens size and weight. Although all the Tamrons have a competitive f2.8 aperture, their end glass has a diameter of 67mm, well below matching Canon or Sony lenses. In the case of this lens, if you can live without that “extra” 20mm on the telephoto end, you get a lens that has like optical quality and is just as fast as the competition, but is physically much smaller and substantially lighter. It is moisture resistant and has coatings to mitigate flare and chromatic aberrations. Two linear motors make autofocus performance comparable to Sony’s own lenses.