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I want to buy a Sigma 180mm F/2.8 EX DG Macro OS HSM Sigma.

What does EX mean?

What does DG mean?

What does OS mean?

What does HSM mean?

marked as duplicate by mattdm, Philip Kendall, John Cavan Jun 16 '14 at 21:38

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  • 2
    EX = high-end series, DG = full frame compatible, OS = optical stabilisation, HSM = hyper-sonic motor – Guffa Jun 16 '14 at 21:04

OS is Optical Stabilization, Sigma's term for a system which moves lens elements to compensate for small camera movements.

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