Sigma 28 70mm f 2 8 dg dn contemporary vs sony fe 24 70mm f 2 8 gm?

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From Sigma 28-70mm f/2.8 DG DN Contemporary: Sigma 28-70mm f/2.8 DG DN Contemporary: A zoom lens by Sigma for Full frame cameras, 28-70mm f/2.8. A small, light f/2.8 standard zoom. Specs - Maker: Sigma - Focal length: 28-70mm (zoom) - Maximum aperture: f/2.8 - Made for: Full frame sensors - Mounts: Sony E, L-Mount - Stabilised: no - Autofocus: yes What it frames like - On full frame (Sony E, L-Mount): as marked, 28-70mm. - On APS-C (Sony E, L-Mount): like 42-105mm on ...

From Sony FE 24-70mm f/2.8 GM: Sony FE 24-70mm f/2.8 GM: A zoom lens by Sony for Full frame cameras, 24-70mm f/2.8. Specs - Maker: Sony - Focal length: 24-70mm (zoom) - Maximum aperture: f/2.8 - Made for: Full frame sensors - Mounts: Sony E - Stabilised: no - Autofocus: yes What it frames like - On full frame (Sony E): as marked, 24-70mm. - On APS-C (Sony E): like 36-105mm on full frame; f/2.8 gives about the depth of field ...

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