Which is better for travel?

The Sigma. At 290 g and 74.5 mm long it fits in a small bag and covers wide to short tele. The Tamron is a large telephoto zoom that suits planned shoots more than walking around.

Can I use the Sigma on a full-frame Sony camera?

Only in APS-C crop mode, which drops resolution. The Tamron 70-180mm G2 is a full-frame lens and uses the whole sensor.

They complement each other rather than overlap. A common pair is the Sigma for everyday framing and the Tamron for portraits, events and distance.

Which has better stabilization?

The Tamron, which has built-in VC optical stabilization. The Sigma has none and depends on the camera body's IBIS.

Is the Tamron worth double the price?

Only if you need 70-180mm reach at f/2.8. For general shooting the Sigma covers more situations for $499.99 versus $999.00.

Which focuses closer?

The Sigma, at 12.1 cm with 1:2.8 magnification at 18mm. The Tamron reaches 1:2.6 at 180mm but only from 0.85 m away.

Sigma 18-50mm f/2.8 DC DN Contemporary vs Tamron 70-180mm f/2.8 Di III VC VXD G2 Lens

These are not substitutes. The Sigma 18-50mm f/2.8 is a compact standard zoom for everyday and travel shooting on Sony APS-C; the Tamron 70-180mm f/2.8 G2 is a full-frame telephoto zoom for reach, portraits and events. Buy the Sigma if you want one small lens that covers most situations; buy the Tamron if you already have a standard zoom and need longer reach with stabilization. The Sigma is $499.99 at Best Buy as of November 4, 2026, and the Tamron is $999.00 at Adorama as of the same date.

Today the Sigma 18-50mm f/2.8 DC DN Contemporary costs $500.00 less at its best price.

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