Canon ef 400mm f 2 8l is iii usm vs canon ef 300mm f 2 8l is ii usm?

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From Canon EF 300mm f/2.8L IS II USM: Canon EF 300mm f/2.8L IS II USM: A prime lens by Canon for Full frame cameras, 300mm f/2.8. Specs - Maker: Canon - Focal length: 300mm (prime) - Maximum aperture: f/2.8 - Made for: Full frame sensors - Mounts: Canon EF - Stabilised: yes - Autofocus: yes What it frames like - On full frame (Canon EF): as marked, 300mm. - On APS-C (Canon) (Canon EF): like 480mm on full frame; f/2.8 gives about the depth of ...

From Canon EF 400mm f/2.8L IS III USM: Canon EF 400mm f/2.8L IS III USM: A prime lens by Canon for Full frame cameras, 400mm f/2.8. Specs - Maker: Canon - Focal length: 400mm (prime) - Maximum aperture: f/2.8 - Made for: Full frame sensors - Mounts: Canon EF - Stabilised: yes - Autofocus: yes What it frames like - On full frame (Canon EF): as marked, 400mm. - On APS-C (Canon) (Canon EF): like 640mm on full frame; f/2.8 gives about the depth of ...

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