Thank you anton for you post it did help. Sorry to be a pain and ask so many questions but I need some more help from anyone out there. I never knew there was so many lenses to chose from. I am buying one piece at a time to keep my "collection" growing. I love wildlife photography and I am looking into a 500mm lens and using a 2X converter. Now I find out there are optical lenses and mirrored lenses. My head is in a spin when I begin to look at lenses and any other equipment. I still love photography and will keep it up, but can anyone tell me the difference in the two lenses and which is better. Size makes no difference, I want quality with the pictures. Also can anyone suggest a book or anyother kind of info out there that can help me. I have 3 books now about photography and taking pictures but I have found none just about equipment only. This equipment is too expensive to make a mistake. So far I have asked 2 camera stores and of course gotten 2 different opinions. I am using a Minolta Maxxum 7000i if that makes any difference. Thank you for any help.