I am currently selling a Sigma 500mm f/4.5 EX APO lens, Pentax fit. There were apparently only six of these made and only one came to the UK. This lens is brilliant for wildlife, the wider maximum aperture meaning the DOF can be controlled better than with smaller aperture zooms. Price is £2800.
Examples:
A Special for our Pentax Users
A Special for our Pentax Users
Best regards
John
John