Canon - RF 24-70mm f/2.8L IS USM vs Tamron - 28-75mm f/2.8 Di III VXD G2

The 28-75mm f/2.8 Di III VXD G2 edges ahead on the Mars Score (64.6 vs 69), but the 4.4-point gap is small enough that the right pick comes down to which spec advantages matter to you.

Pick the RF 24-70mm f/2.8L IS USM if you care most about optical stabilization. The biggest gaps in its favor are optical stabilization. The single most decisive one: Has Optical stabilization.

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, min focal, max focal. The single most decisive one: Weight — 360.00 g less. 540 vs 900.

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

Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.