I am interested in pursuing a career in wildlife cinematography, but I am currently unable to purchase my own equipment. I have access to a Sony HDRFX1, but for filming wildlife, I really need larger than a 12x zoom. Since I don't really have any other choice, I am considering shelling out some money for a teleconverter lens that screws on to the front of the FX1. I know that these converter lenses are not ideal, but I don't have interchangeable lenses and I think I might still benefit from one of these.
I am wondering if anyone has had experience using teleconverters, especially on HD cameras. If there are downsides, especially to cheap conversion lenses, what are they and how will I see these disadvantages in my footage? Here are links to the two I have been considering. Obviously there is a big price difference. I can probably only afford the cheaper one myself, but may be able to get some money from elsewhere to purchase something more expensive.
http://stores.channeladvisor.com/47stphoto/items/item.aspx?itemid=4398667
http://www.digitalfotoclub.com/sc/from-froogle.asp?id=964730502&rf=froogle&dfdate=5_22_2009
Any help would be greatly appreciated. Cheers.

