Which is better for portraits?

The Tamron gives a longer equivalent reach, about 105mm at the long end, which flatters faces. The Sony has better sharpness and smoother bokeh from 11 blades. On a full-frame body, the Sony wins on image quality.

Will the Tamron fit my full-frame Sony?

It mounts on Sony E, but it is an APS-C lens. On a full-frame body it either crops to APS-C or vignettes heavily. Buy the Sony for full frame.

Is the Sony worth the extra money?

Only if you shoot full frame and need the sharpness, autofocus speed and weather sealing. At $2,448.00 versus $599.00, the Tamron is the better value for APS-C shooters.

Which has better autofocus?

The Sony. Its floating focus mechanism and linear motors track faster and quieter, which matters for sports and video. The Tamron's RXD motor is fine for everyday use.

Which is better for video?

The Tamron has minimal focus breathing and a close 0.19 m minimum focus, which helps on a gimbal. The Sony focuses faster and is sharper, but it costs far more.

Do either have image stabilization?

Neither lens lists optical stabilization. Both rely on the camera body's in-body stabilization, so check your body has it.

Sony FE 24-70mm f/2.8 GM II vs Tamron 17-70mm F2.8 Di III-A VC RXD

These are not substitutes. The Sony FE 24-70mm f/2.8 GM II is a full-frame G Master standard zoom at $2,448.00 at bhphotovideo.com as of November 6, 2026. The Tamron 17-70mm F2.8 Di III-A VC RXD is an APS-C zoom at $599.00 at Abt Electronics & Appliances as of November 6, 2026. Buy the Sony if you shoot full frame and want the best optics and autofocus. Buy the Tamron if you shoot a Sony APS-C body and want f/2.8 coverage for a quarter of the price.

Today the Tamron 17-70mm F2.8 Di III-A VC RXD costs $1,849.00 less at its best price.

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