Quote from JBP on March 10, 2023, 5:39 pm

I believe this is the good Bigma. K mount, $389... https://www.mpb.com/en-us/product/sigma-50-500mm-f2f45-63-apo-dg-os-hsm-pentax-fit/sku-1868903

https://www.pentaxforums.com/userreviews/sigma-50-500mm-f4-5-6-3-os-hsm.html