Sigma has officially announced its intention to stop producing lenses for the Pentax K-mount. Due to the dwindling number of Pentax users, says Sigma, the brand will shift focus and resources towards developing lenses for mirrorless cameras. The news first appeared on the Sigma Czech Republic Facebook page, where the brand announced that it has decided “to completely end the production of Pentax K-mount lenses this fall” in order to “focus more on developing and supporting mirrorless systems, which they…