Hai Everyone, I got to consult you regarding purchase of new lens. I am interested in wildlife photography and am looking for a telephoto lens at the cheapest prices. I got through two lens 1. Opteka 500mm f/8 telephoto lens - $70 2. Kenko 420-800mm f/8.3-16 lens - $160 I didn't find many reviews regarding both the lens and would like to know your opinion on the issue. I would be very happy if there's anyone who had a feel of any of the two lens and would like to share their experiences. One more important doubt --- I have a Nikon D50 and Sony Alpha100 cameras. As they were providing T-Mount adaptors for both of the lens, is it sufficient if I buy one lens(with Nikon T-mount) and an Sony T-mount? amiably, Ravi Kiran.