Summary: I didn't realize how oversized this lens was. But I never was able to use the lens because my LUMIX DMC-G1 would not recognize the lens. The mount adapter and 2X telephoto lens that came with the Opteka were very poor quality, would not separate after assembled and I do not believe they could...
Summary: Any review of this lens has to be prefixed with the phrase "for the money" and yes, for the money this is great. Be warned it is so long at 1000mm that you really really need a tripod or monopod. In 500 mode you can hold it if you have something to brace your arm against.
Summary: It's not a great lens but for a great 1000mm lens you have to pay $12,000. For the price it's great. Construction is fine, not too heavy, it's completely manual in operation and the optical quality although a little milky it's a lot better than what I expected for the price.
Summary: The lens by itself is quit sharp actually, although you need to work hard to get the manual lens to focus right. It's quite frustrating though to focus with the double zoom adapter and it doesn't give great results, so you really need to struggle to have a focus.
Summary: This lens is awesome! It of course, needs a tripod to function properly, but this is as expected with a mirror 500mm lens. I have taken and continue to take, absolutely awesome photos of the moon and landscape with this lens. It could not be obtained better even at 400 dollars, I'm sure.