I was recently selling some of my old Pentax lenses and was surprised by the level of interest and number of bids for what are quite specialist and now rather old lenses. The lenses were manual focus but genuine Pentax and with very wide maximum apertures.
I found out shortly afterwards that there is a big demand for Pentax lenses to use with Canon EOS cameras for shooting video. With video the focus is manual anyway and the lenses are such high quality that they are a bargain for the price.
As an example you could pay £600 for a Canon 135mm lens but the Pentax version will set you back the princely sum of £20! You do need to buy a Pentax K to Canon EOS adapter to allow you to use the lens on your Canon 5DII camera but these can be bought on Ebay for around £10. One such example is here
With a total outlay of £30 you can have an excellent quality lens to use on your Canon 5D Mark 2 for video and get some stunning results.
