Sigma 500mm f 5 6 dg dn os sports vs sony fe 600mm f 6 3 gm oss?

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From Sigma 500mm f/5.6 DG DN OS Sports: Sigma 500mm f/5.6 DG DN OS Sports: A prime lens by Sigma for Full frame cameras, 500mm f/5.6. A comparatively light 500mm prime for wildlife. Specs - Maker: Sigma - Focal length: 500mm (prime) - Maximum aperture: f/5.6 - Made for: Full frame sensors - Mounts: Sony E, L-Mount - Stabilised: yes - Autofocus: yes What it frames like - On full frame (Sony E, L-Mount): as marked, 500mm. - On APS-C (Sony E, L-Mount): like 750mm ...

From Sony FE 600mm f/6.3 GM OSS: Sony FE 600mm f/6.3 GM OSS: A prime lens by Sony for Full frame cameras, 600mm f/6.3. A 600mm prime of about a kilogram, for wildlife hand-held. Specs - Maker: Sony - Focal length: 600mm (prime) - Maximum aperture: f/6.3 - Made for: Full frame sensors - Mounts: Sony E - Stabilised: yes - Autofocus: yes What it frames like - On full frame (Sony E): as marked, 600mm. - On APS-C (Sony E): like 900mm ...

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