Sony - FE 135mm f/1.8 GM vs Tamron - 28-75mm f/2.8 Di III VXD G2

The FE 135mm f/1.8 GM is the clear pick on raw spec strength, leading by 15.3 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.

Pick the FE 135mm f/1.8 GM if you care most about min focal / max focal. The biggest gaps in its favor are min focal, max focal.

Pick the 28-75mm f/2.8 Di III VXD G2 if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are weight.

Both ship with comparable weather sealed, optical stabilization, so those specs do not separate the two — focus on the differences below.

Bottom line: the FE 135mm f/1.8 GM is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.