Tamron's earlier 24-70mm f/2.8 for A-mount — SP quality with USD motor for Sony DSLR system.
The Tamron SP 24-70mm f/2.8 Di USD launched in 2008 as Tamron's professional standard zoom with USD motor, available for Sony A-mount among others. The SP designation indicates Tamron's premium optical tier with constant f/2.8 aperture.
Optically good — sharp in the centre throughout with respectable edge performance. Constant f/2.8 for consistent exposure. USD motor provides fast, quiet AF. The SP quality is a step above Tamron's standard line. No stabilisation — relies on body SteadyShot.
Sony A-mount with 82mm filter thread. Approximately 825g. No weather sealing. Full-frame coverage. Minimum focus distance 38cm. SP professional build quality. USD motor.
Available used at budget to mid-range prices. A-mount is discontinued. The Tamron 24-70mm G2 improved significantly. Adapts to E-mount via LA-EA adapters but native FE lenses are better. For existing A-mount users needing a constant f/2.8 standard zoom.