Pentax hd da 21mm f 3 2 al limited vs sigma 30mm f 1 4 dc hsm art?

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From Pentax HD DA 21mm f/3.2 AL Limited: Pentax HD DA 21mm f/3.2 AL Limited: A prime lens by Pentax for APS-C cameras, 21mm f/3.2. Specs - Maker: Pentax - Focal length: 21mm (prime) - Maximum aperture: f/3.2 - Made for: APS-C sensors - Mounts: Pentax K - Stabilised: no - Autofocus: yes What it frames like - On APS-C (Pentax K): like 32mm on full frame; f/3.2 gives about the depth of field of f/4.8 there. - On the larger-sensor bodies of Pentax K: ...

From Sigma 30mm f/1.4 DC HSM Art: Sigma 30mm f/1.4 DC HSM Art: A prime lens by Sigma for APS-C cameras, 30mm f/1.4. Specs - Maker: Sigma - Focal length: 30mm (prime) - Maximum aperture: f/1.4 - Made for: APS-C sensors - Mounts: Canon EF, Nikon F, Pentax K - Stabilised: no - Autofocus: yes What it frames like - On APS-C (Nikon F, Pentax K): like 45mm on full frame; f/1.4 gives about the depth of field of f/2.1 there. - On ...

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