This is an A-mount lens that I want to use on my a77II. I bought this to replace my old Sony Beer Can 75-300 lens that I bought in 2006. Both lenses are good, both are full frame, but the SA170300G has better glass, faster autofocus and a super fast autofocus motor that doesn't make any noise. For me, this is very important when shooting a video. It's a bright lens, sharp and the Leica glass is top notch. The difference between this lens and the SSMII is that the SSMII has more heavily coatedβ¦