Best wide angle lens for the pentax k 50?

Here is what the site says about that.

From Pentax K-50: Pentax K-50: A DSLR by Pentax with a 16.3-megapixel APS-C sensor, announced in 2013. A weather-sealed entry-level body that can also run on AA batteries with an optional holder. Specs - Maker: Pentax - Mount: Pentax K - Sensor: APS-C, 23.5 x 15.6mm, crop factor 1.5 - Resolution: 16.3 megapixels - Stabilisation: in the body - Announced: 2013 - Type: DSLR Focal lengths on it Lenses frame like 1.5 times their focal ...

From Laowa 15mm f/4 Wide Angle Macro: Laowa 15mm f/4 Wide Angle Macro: A macro lens by Laowa for Full frame cameras, 15mm f/4. An ultra-wide that focuses to 1:1.

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