Posted 14 January 2012 - 10:32 AM
You don't say in your post whether this lens is for the current Pentax 'K' mount or the older thread mount that Pentax used many years ago. A few manufacturers made adapters that would allow you to attach this lens to a Nikon, but with no communication with the camera. You would be able to focus, zoom and shoot manually, but you would have to meter with the lens aperture in what was called "stop-down" mode. The aperture would remain closed to the current setting even between shots. Your viewfinder image would darken as you closed the aperture and critical focus would become difficult. Depending on the age of your lens, these adapters could vary scarce.
I hope this helps.