Amazon.com : Commander Optics 650-1300mm f/8-16 HD Telephoto Zoom Lens for Pentax K-1, K-S2, K-S1, K-500, K-70, K-50, K-30, K5 IIs, K-7, K-5, K-3 II, K-2, K100D, K110D and K10D Digital SLR
650-1300mm Telephoto Lens KIT For Pentax K7 K5 KR KX K50 K30 K1 K3 II K-S2 K70 814733012267 | eBay
Buy Opteka 420-800mm f/8.3 HD Telephoto Zoom Lens for Pentax K-70, K-50, K-3 II, KP, K-1, K-S2, K-S1, K-500, K-30, K5 IIs, K-7, K-5, K-2, K20D, K100D, K110D and K10D Digital SLR
Jintu 420mm-800mm Telephoto Lens Camera Lenese + T2 Adapter For Pentax K Mount K3 K5 K7 K20d K-s1 K-50 K5 Ii K-7 K-3 K2 Camera - Camera Lenses - AliExpress