Which is better for portraits?

The Sigma. Its F2.8 aperture and 50mm end give blurrier backgrounds and better low-light performance. The Tamron at 70-300mm can compress backgrounds but starts at F4.5.

Can I use both on the same camera?

Yes, if you have an APS-C Sony body. The Sigma is APS-C only, while the Tamron covers full-frame and APS-C. On APS-C the Tamron gives a 105-450mm equivalent view.

Which is better for sports and wildlife?

The Tamron, because 300mm reach matters more than aperture in daylight. The Sigma tops out at 50mm, which is far too short for most field sports.

Is the Sigma worth $150 more?

Only if you need the F2.8 aperture and small size. The Tamron is cheaper but covers a completely different range, so compare against other standard zooms, not against the Tamron.

Which is better for video?

The Sigma, for its constant aperture, quiet autofocus and close focus. The Tamron's aperture shifts as you zoom, which causes exposure jumps.

Do either have image stabilization?

Neither lens has optical stabilization. Both rely on the camera body's stabilization, which most recent Sony bodies have.

Sigma 18-50mm F2.8 DC DN Contemporary Lens For Sony E-Mount vs Tamron 70-300mm F/4.5-6.3 Di III RXD

These are not substitutes. The Sigma 18-50mm F2.8 is a fast standard zoom for APS-C Sony bodies; the Tamron 70-300mm is a slow telephoto zoom for full-frame and APS-C. Buy the Sigma if you want one small, bright walk-around lens. Buy the Tamron if you need reach for sports, wildlife or outdoor events. As of November 6, 2026, the Sigma is $499.00 at Best Buy and the Tamron is $349.00 at Walmart.

Today the Tamron 70-300mm F/4.5-6.3 Di III RXD costs $130.00 less at its best price.

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